The opening and closing of _____________in your heart create the lub-dub sound and prevent the backflow of blood.

What goes in the blank?

Answers

Answer 1

Answer:

Heart valves or the closure of the mitral and tricuspid atrioventricular (AV) valves at the beginning of ventricular systole and the closure of the aortic valve and pulmonary valve at the end of ventricular systole.

Explanation:

The heart tone “lub,” or S1, is caused by the closure of the mitral and tricuspid atrioventricular (AV) valves at the beginning of ventricular systole.

The heart tone “dub,” or S2 ( a combination of A2 and P2), is caused by the closure of the aortic valve and pulmonary valve at the end of ventricular systole.


Related Questions

Why is it important to understand challenges in a species environment in order to understand the species evolution? Relate your answer to what Darwin referred to as "the struggle for survival"

Answers

Answer:

The Struggle for Survival refers to the fight between organisms to survive by having access to the increasingly scarce resources in the environment brought upon by population increase.

Darwin believed that evolution was brought about by external pressures arising from this struggle for survival as species would have to adapt to the unique challenges in their environment to be able to better access resources.

This is why one must understand the challenges in an environment to understand why species in that environment evolved the way they did.

A rabbit eats some grass. A fox eats that rabbit. A wolf comes along and eats the fox. What is this an example of:
decomposers
food chain
abiotic factor
fossil record​

Answers

that’s the food chain
your welcome

Which system is responsible for breaking down food?


A.endocrine system


B.digestive system


C.excretory system


D.lymphatic system

Answers

Answer:

B

Explanation:

Digestive is your stomach, breaks down food.

Answer:

B

Explanation:

The digestive system is where large food particles are broken down into smaller bits for easy absupbtion

What part of earth absorbs most sunlight

Answers

Answer:

The atmosphere

Explanation:

Answer:

The equator.

Explanation:

"The equator receives the most solar radiation in a year. The difference in the amount of solar energy the land receives causes the atmosphere to move the way it does."

I wasn't so sure about this question. During my research, the internet says atmosphere, equator, and then oceans. I believe it's more of the equator than anything, but there are three choices to choose from.

I hope this helps!

Where are many critical biodiversity hotspots located?

Answers

Answer:

Tropical forests are typically biodiversity hotspots and are usually filled with endemic species. The Upper Amazonia/Guyana Shield, the Congo Basin, and the New Guinea/Melanesian Islands have the highest number of endemic terrestrial (land-living) species on Earth

Explanation:

hope this helped:)

HELPPPPP :p

Explain how precipitation happens. Use complete sentences and give at least two supporting details.

Answers

Answer:

In a general aspect, humid and warm air moves to lower latitudes or in altitude, losing heat and getting colder. Its humidity condenses and causes precipitation. Depending on the air movement there are different kinds of rain.  

Explanation:

At a global level, it occurs unequal warming of the atmosphere, which depends on many factors and varies with latitude. This occurs because solar radiation reaches the earth differently at different latitudes, resulting in big convective cells of atmospheric circulation: Hardley cell, Ferrel cell, and Polar cell.    

A convective cell is the movement of the humid air among different latitudes. Air moves from higher latitudes to lower latitudes, getting warm, getting less dense, and ascending. As the air gets higher in altitude, it´s density and pressure decrease, so the air tends to expand with elevation in response to the reduced pressure. Gases in expansion experiment adiabatic cooling, losing caloric energy as their molecules move getting farther away from each other. As the air gets higher, it gets colder, and hence, denser. The result is that descends again. Humidity gets denser and precipitates.

• Rain is controlled by temperature on the earth´s surface, atmospheric global air circulation, the position of the mountains and oceans, closure to the oceans.  

• There are different kinds of precipitations according to their origin.

i. Convective precipitation: These are the most typical ones. Air gets warmer and less dense, elevating in altitude with humidity. On the way, it starts to get colder, and the humidity condenses, resulting in precipitation. Depending o the degree of condensation, the precipitation might be in a liquid state (rain), semisolid-state (snow), or solid-state (hail).

ii. Frontal Precipitations: They occur when a polar front coming from higher latitudes collide with a warm front coming from lower latitudes, resulting in a strong rain. This is typical of grasslands or temperate forests (approximately 40 º latitude)

iii. Orographic Precipitations: They occur when humid wind ascends by a mountain range, causing its adiabatic cooling, condensing the humidity, and precipitating.  

Monomers linked together to form a polymer could be described as beads in a multicolored necklace. Which statement about monomers is true with respect to the above analogy?

A. Monomers in a polymer could be linked in various ways.
B. Monomers in a polymer are of different types.
C. Monomers in a polymer look different but are structurally similar.

Answers

The answer is B

Monomers linked together to form a polymer could be described as beads in a multicolored necklace because monomer in a polymer are of different types.

4. Discuss the role of necrohormones

Answers

Answer:

neurotransmitter is a chemical messenger that carries, boosts, and balances signals between neurons (also known as nerve cells) and target cells throughout the body.

How does the amount of light affect how plants grow?

Answers

Answer:

Light is an essential factor in maintaining plants. The rate of growth and length of time a plant remains active is dependent on the amount of light it receives. Light energy is used in photosynthesis, the plant's most basic process.

Explanation:

Hope it helped :)

Below is an image of a well. Explain what type of well this is and how it works

Answers

Answer:

This is an artesian well. An artesian well is simply a well that doesn't require a pump to bring water to the surface. This occurs when there is enough positive pressure in the aquifer to bring the water to the surface. An artesian aquifer is confined between impermeable rocks or clay which causes this positive pressure.

Explanation:

This is the answer for the pic I put but sorry if it's not the right well

Food intoxications can cause huge economical and health problems. Identify the steps that might occur leading to a food intoxications by Staphylococcus aureus and Clostridium botulinum.
Staphylococcus aureus Clostridium botulinum
Surviving endospores germinate grow, and produce toxin in canned foods
Other bacteria in the food are killed/inhibited by cooking/salty points Skipped canning processes. Canned foods are anaerobic eBook References A person ingests the toxin-containing food, resulting in staphylococcal enteritis in two to six hours. enterotoxin when the food is held at room temperature for several A person ingests the toxin- containing food. Symptoms of botulism n in 12-36 hours. Bacterial endospores contaminate many difterent foods. A food handler carries the pathogen in their nasal caviety and transfers it to the food via their hands

Answers

Answer: It will result in the development of Staphylococcal enteritis.

Explanation:

Staphylococcus aureus and other bacteria are responsible for contaminating the food are killed or inhibited by the cooking the food under salty conditions. The salt will break the cell walls of the bacteria. If a person consumes the food contaminated with Staphylococcus aureus then he is expected to be affected by the food poisoning disease called as Staphylococcal enteritis.

Answer????????????????

Answers

Answer:

carbon dioxide

Explanation:

Which of the following is responsible for sensing excessive strength to protect the muscle

Answers

Answer: golgi tendon organ

Explanation:

When you lift weights, the golgi tendon organ is the sense organ that tells you how much tension the muscle is exerting. If there is too much muscle tension the golgi tendon organ will inhibit the muscle from creating any force (via a reflex arc), thus protecting the you from injuring itself.

Carnations with red, smooth petals are crossed with carnations with white, rough petals. In the F1, all the petals are pink and smooth. The F1 intercross yields the following F2:3/16 red, smooth6/16 pink, smooth3/16 white, smooth2/16 pink, rough
1/16 red, rough1/16 white, rougha) What are the parental genotypes?b) What are the F2 genotypes and phenotypes?c) What conclusions can be made about the allelic and gene interactions for both the petal color and texture alleles?

Answers

Answer:

a) What are the parental genotypes? RRSS and rrss

b) What are the F2 genotypes and phenotypes?

   F2) 3/16 RRSS + RRSs (red, smooth)

     6/16 RrSS + RrSs (pink, smooth)

     3/16 rrSS + rrSs (white, smooth)

     2/16 Rrss (pink, rough)

     1/16 RRss (red, rough)

     1/16 rrss (white, rough)

c) What conclusions can be made about the allelic and gene interactions for both the petal color and texture alleles? For petal color, it occurs incomplete dominance, being R the dominant allele for red and r the recessive allele for white, together expressing pink in heterozygosis. For texture, it occurs complete dominance of the allele codifying for smooth, S, over the allele codifying for rough, s.

Explanation:

Due to technical problems, you will find the complete answer and explanation in the attached files.

onsider a scenario where a native plant population is growing at it's carrying capacity in a community. The seed of an invasive species is brought in by a squirrel, which then germinates, grows and reproduces resulting in the establishment a population of this invasive plant species. The invasive species has very similar niche as the native plant species. How do you predict the invasive plant population to be affected by the presence of this native species

Answers

The given question is incomplete, the complete question is:

Consider a scenario where a native plant population is growing at it's carrying capacity in a community. The seed of an invasive species is brought in by a squirrel, which then germinates, grows and reproduces resulting in the establishment a population of this invasive plant species. The invasive species has very similar niche as the native plant species. How do you predict the native plant population to be affected by the presence of this invasive species?

The invasive species fitness will be limited by the native plant species

The native plant carrying capacity will go down, relative to that prior to the invasive species arrival

There will be no change to the native plant population

The invasive species will grow unchecked and exponentially

No listed answer is correct

Answer:

The correct statement is the fourth one, that is, the invasive species will grow exponentially and unchecked.

Explanation:

The fitness of the invasive species will not get restricted by the native species. Though the opposite takes place as the original niche of the local species does not possess the natural predator for the invasive species. Therefore, invasive species emerge fitter and reproduce exponentially without population control.

The carrying capacity of the native species will not go down before the arrival of the invasive species, however, will go down post its arrival.  

As the invasive species has no natural predators, one can witness a substantial reduction in the population of the local plant population. The invasive species will utilize the niche of the local plant, therefore, resulting in the reduction of the native species population, as they have share habitat, food resources, and other natural resources.  

It is correct that the invasive species will grow without any control. An outbreak of invasive species generally takes place due to the absence of its natural predators in the ecosystem at the time of its introduction. Hence, the correct statement is the fourth one.

Invasive species establish in a new area, overgrow, and negatively interact with native species. The correct option is  4). The invasive species will grow unchecked and exponentially

-----------------------------------

Let us firts reviw some framework.

When talking about dispersion, we refer to the change in a species' range or distribution area.

When species move and establish in a new area, out of their original distribution range, they might be considered exotic or invasive, according to their

reproductive rate,

population growth, and

interaction with native species.

The introduction of invasive species has ecological, economic, socio-cultural consequences.

Once an invasive species has been established, it overgrows.

In the new areas, these species have less environmental pressure and better conditions than in their origin area -fewer predators, more resources, better nitches-.

These factors favor their establishment because they are adapted to surviving under harder conditions.  

They interact with native species by competing for resources such -water, place, radiation, exposure, shelter, food, etcetera-.  

They can also become significant predators of native species, consuming a wide diversity of prey items, and in many cases, there are no native species that may prey on them.

They provoke significant damages in the structure of native ecosystems, causing severe damage in endemic species.

They produce ecological imbalances in the trophic chains and the dynamics of communities. Invasive species are uncontrollable.

As they expand, they can also affect human in an economic manner and has socio-cultural effects. Many invasive species might cause crops loss by eating cultures. They attack farm animals. They affect buildings and other structures or ships by eating wood. They might even attack humans and cause health problems.

According to this information, we can answer the question.

We need to predict how NATIVE species are affected by INVASIVE species.

The options are,

1) The invasive species fitness will be limited by the native plant species

When talking about invasive species, this is not an option. Invasive species always affect the fitness of native species. So this option is not correct.  

2) The native plant carrying capacity will go down, relative to that prior to the invasive species arrival

The carrying capacity will still be the same. But resources availability will decrease faster because both species have the same requirements. They compete for the same resources. This option is not correct.

3) There will be no change to the native plant population

The will occur changes for the native population for sure. It will be affected by the presence of invasive species. So this option is not correct.  

4) The invasive species will grow unchecked and exponentially

Invasive species population will express an uncontrol exponential growth during its establishment phase.

This plant species find the perfect conditions to reproduce and increase its population size.

It finds available space, no predators, water and nutrients availability, proper light exposure, among others.

They can successfully compete with native species, displacing them and getting more space.  

THIS IS THE CORRECT OPTION

5) No listed answer is correct

Not correct

---------------------------------------

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Which phrase best describes the function of the cell membrane?
O sends chemical signals
O allows things to move in + out of the cell
O rigid structure + support
o creates proteins
HELP

Answers

Answer:

i dont knowExplanation:

There are different forms of energy and one form of energy can be converted into another. When we light a wax candle, the process is highly exothermic and on burning, the chemical energy of the wax gets converted into heat and light. A good source of energy is to be selected for the choice of work to be done. In ancient times, wood was the most common source of heat energy. We, in our daily lives, use various energy sources for doing the work. Nowadays we use diesel and electricity to run trains. We also use fossil fuels in vehicles which has some serious disadvantages, mainly air pollution. The recent example of air pollution was ‘Smog’ in the National Capital Region of Delhi. This pollution was a result of burning ‘Parali’ in northern states of the country, which affected the eyes and also caused serious respiratory problems.
4(a) State the energy conversion that takes place when we light a wax candle. 1
4(b) List two criteria of selecting a source of energy for a specific work. 1
4(c) Write the names of two fossil fuels. 1
4(d) why are we looking at alternate sources of energy? 1

Answers

Answer:

shiii tbh thats hard

Explanation:

plsssss help me :) thank you luv

Answers

Answer:

liquid 1 and 4 because it is the same melting point

Explanation:

Answer:

liquid 1 and 2

Explanation:

why do small pp YEEEEEEEEEEEEEEEEEEEE

Answers

Answer:

i like them big so i wouldnt know

Explanation:

Iemme stop lol

Answer:

yeeeeeeeeeeeeeeeeeeee

Item 3
Which organ is found in the excretory system?


stomach


heart


bladder


large intestine

Answers

Answer:

Large intestine

Explanation:

Excretory Organs include- skin, liver, large intstine, lungs, and kidneys

Hope this helps

Answer:

skin, liver, large intestine, lungs, and kidneye

Explanation:

Google

One codon has the instructions to make

Answers

Answer:

1 protein

Explanation:

PLS HELP WILL MARK BRAINLIEST!!!!!

Which statements are true of all plants? Select four options.

O Most plants are vascular.
O All plants are multicellular.
O All plants are eukaryotic.
O Most plants are autotrophic.
O All plants need sunlight.
O Most plants reproduce sexually.

Answers

Answer:

a, b, c, and d

Explanation:

replicate the following dna strand TAT-TAG-ATT-ACA

Answers

The replicated strand of DNA is. ATA-ATC-TAA-TGT

Adenine pairs with Thymine
Guanine pairs with Cytosine

If you have trouble remembering just think about it as curvy letters stick together(C,G), and straight letters go together (A,T)

The replication of the given DNA strand TAT-TAG-ATT-ACA is ATA-ATC-TAA-TGT.

What is DNA replication?

DNA replication may be defined as a type of biological process through which the genomic DNA of an organism gets copied into the cell during the time of cell division. During this process, the two identical replicas of DNA are produced from one original DNA molecule.

According to the context of this question, when it comes to DNA replication, adenine is replaced by thymine and vice-versa while guanine is replaced by cytosine and vice-versa. So, the amount of adenine remains equal to the amount of thymine and the amount of guanine remains equal to cytosine.

Therefore, the replication of the given DNA strand TAT-TAG-ATT-ACA is ATA-ATC-TAA-TGT.

To learn more about DNA replication, refer to the link:

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What is the difference between domestication and natural selection?

Answers

Answer:

By definition, natural selection is the survival of the fittest.

Explanation:

Natural selection, in itself, is not a generator or creator of evolutionary novelties, but it only exposes certain variants.

Variants do not arise under the induction of the environment, but randomly, by chance, by a combination of genetic material, something that already exists in the genetic fund of a species.

Domestication is a term used for the process by which various biological organisms adapt to survive in society or through the work of human beings.

What is the process where water enters
the atmosphere by evaporating from the
leaves of plants?
A. Liquification
B. Transpiration
C. Sublimation

Answers

Answer:

B/Transpiration

Explanation:

Transpiration is evap- oration of liquid water from plants and trees into the atmosphere. Nearly all (99%) of all water that enters the roots transpires into the atmosphere. ... Sublimation is the process where ice and snow (a solid) changes into water vapor (a gas) without moving through the liquid phase

The is about determining if you are the way you are because of your
genes or because of your upbringing.
A. continuity versus stability debate
B. biology versus environment debate
C. science versus arts debate
D. nature versus nurture debate

Answers

D — this is the nature vs. nurture debate

Use the ideas of natural selection to suggest how woolly mammoths may have developed..

Science !!
PICTURE BELOW

Answers

Answer:

thats crazyyyy

Explanation:

Woolly mammoths developed thick fur and large ears to survive in cold climates through natural selection.

The cold climate of the Pleistocene epoch favored the survival of animals that were well-adapted to cold weather. Woolly mammoths had thick coats of fur that helped to keep them warm, and they also had large ears that helped to dissipate heat. Woolly mammoths had a long trunk.

The trunk of the woolly mammoth was used for a variety of purposes, including gathering food, drinking water, and communicating with other mammoths. The trunk was also a valuable tool for helping the mammoth to survive in cold weather.

For example, the mammoth could use its trunk to blow snow away from its food or to reach food that was buried under the snow. Woolly mammoths were social animals. Woolly mammoths lived in herds, which helped them to survive in cold weather. The herds provided protection from predators and helped to keep the mammoths warm.

To know more about the Woolly mammoth, here

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Edward is extremely romantic and wants to give Bella an entire bouquet of pink snapdragons, her favorite flower. Unfortunately, Edward only has red snapdragons in his greenhouse. In order to produce the most number of pink snapdragons, what color flower should Edward cross with his red snapdragons?


Can someone help me with this question?


Thanks.

Answers

White snapdragons because red and white make pink

if the recessive allele for cystic fibrosis is represented as c

Answers

i don’t understand what you’re asking

cc- recessive has the disorder

Explanation:be my friend on brainly


It took millions of years for coal to form. The process began when giant plants died. What happened to the plants RIGHT AFTER this?
A) They turned into sedimentary rock.
B) They sank to the bottom of swamps.
C) They hardened because they lost oxygen.
D) They changed because of pressure and heat.

Answers

Answer:

B. They sank to the bottom of swamps.

Explanation:

I majored in Biology.

Answer: B) They sank to the bottom of swamps.

Explanation:

Other Questions
Please helpWhat are the three prairie provinces in Canada? I need the answer to this ASAP please!!!!! Select the correct text in the passage.In which sentence does the author most clearly define his argument?adapted from The Goal of Sending a Man to the Moonby John F. Kennedy If we are to win the battle that is now going on around the world between freedom and tyranny, the dramatic achievements in space which occurred in recent weeks should have made clear to us all the impact of this adventure on the minds of men everywhere. Since early in my term, our efforts in space have been under review. With the advice of the Vice President, we have examined where we are strong and where we are not, where we may succeed and where we may not. Now it is time to take longer stridestime for a great new American enterprisetime for this nation to take a clearly leading role in space achievement. This in many ways may hold the key to our future on earth. Recognizing the head start obtained by the Soviets with their large rocket engines, we nevertheless are required to make new efforts on our own.For while we cannot guarantee that we shall one day be first, we can guarantee that any failure to make this effort will make us last.We take an additional risk by making it in full view of the world, but this very risk enhances our stature when we are successful.We go into space because whatever mankind must undertake, free men must fully share. I therefore ask the Congress, above and beyond the increases I have earlier requested for space activities, to provide the funds which are needed to meet the following national goals: First, I believe that this nation should commit itself to achieving the goal, before this decade is out, of landing a man on the moon and returning him safely to the earth. No single space project in this period will be more impressive to mankind, or more important for the long-range exploration of space. None will be so difficult or expensive to accomplish.In a very real sense, it will not be one man going to the moonif we make this judgment affirmatively, it will be an entire nation.For all of us must work to put him there. Secondly, an additional 23 million dollars, together with 7 million dollars already available, will accelerate development of the Rover nuclear rocket.This gives promise of some day providing a means for even more exciting and ambitious exploration of space.This will perhaps go beyond the moon, perhaps to the very end of the solar system itself. Third, an additional 50 million dollars will make the most of our present leadership, by accelerating the use of space satellites for world-wide communications. Fourth, there will be an additional 75 million dollarsof which 53 million dollars is for the Weather Bureau. This will help give us at the earliest possible time a satellite system for world-wide weather observation. Let it be clear that I am asking the Congress and the country to accept a firm commitment to a new course of actiona course which will last for many years and carry very heavy costs: 531 million dollars in fiscal '62an estimated seven to nine billion dollars additional over the next five years. If we are to go only half way, or reduce our sights in the face of difficulty, in my judgment it would be better not to go at all.1.)For while we cannot guarantee that we shall one day be first, we can guarantee that any failure to make this effort will make us last.2.)We go into space because whatever mankind must undertake, free men must fully share.3.)In a very real sense, it will not be one man going to the moonif we make this judgment affirmatively, it will be an entire nation.4.)This gives promise of some day providing a means for even more exciting and ambitious exploration of space. How did Tom meet Myrtle? a On the train b At George's garage c At Gatsby's d She came to his house with friends 5. The Hudson family went out to dinner. The meal cost $57.50. If they also left a 15% tip, approximately how much did the entire dinner cost? the __________ was the incharge of justice under shivaji A paragraph about the fall of the Western Roman Empire using your own words please use your own words. How do you think Robin Hood became an outlaw? Write a paragraph stating your opinion. Remember, your opinion is what you think and feel about the situation, not a retelling of the events of the story. Garret paid 20$ for five movie tickets find the cost per ticket Megan paid 22$ for 7 books determine the cost per book un cuadro tiene 12 cm en sus lados cuanto mide su area y su perimetro Why is the historical setting of "Master Harold" . . . and the Boys important to the themes of the play? What is the solution(s) to the equation? Use algebra only, no graphing. 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What is one result of the Aryans settling into a more stable life in India?The Dravidian culture became the dominant culture in India.Social classes were removed as an element of Indian culture.Sanskrit became the most common language of educated Indians.A nomadic existence became the most common lifestyle of Indians.please hurry in a middle of a test What is cybercrime?Describe some of the various cybercrimes?What are the laws that govern cybercrimes?What can we do to prevent being a victim?Remember to provide examples.