For what percentage of the earth existance have hominids exsisted?

Answers

Answer 1

Answer:It took 13.8 billion years of cosmic history for the first human beings to arise, and we did so relatively recently: just 300,000 years ago. 99.998% of the time that passed since the Big Bang had no human beings at all; our entire species has only existed for the most recent 0.002% of the Universe

Explanation:


Related Questions

any one interested in revising Biology nutrition in animals?​

Answers

Answer:

yes...let's do it am interested

Answer:

yeah I am interested in revision

1. Science has limits and cannot answer all questions. Define science, and then give an e question that science is able to answer. ​

Answers

Answer:

science is the study of the structure and behavior of our world and universe.

Things science cannot explain

Why ice is slippery

How many species of animals and living things there are

Explanation:

19. Dax just completed a report on car transportation. He concluded that gasoline
prices will likely rise significantly in the years to come and recommends lower-
cost car transportation for the future. Dax's younger sister, Ava, just completed a
report on air pollution. Ava concluded that gasoline-powered cars cause too
much pollution and recommends that they should not be used in the future.
Which of the following is a solution for the future that would follow both Dax's
and Ava's recommendations?

Answers

A solution for the future that would follow both Dax's and Ava's

recommendations will be to develop cars that run on fuels that pollute less

and cost less than gasoline.

The use of other fuels such as electricity is cheaper than gasoline and will

help tackle the problem of the rising cost of gasoline.

The use of alternative sources doesn't involve the release of gases such as

carbon monoxide etc which pollutes the environment as carbon isn't burned

when electricity is used.

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Answer:

development of cars that run on fuels that pollute less and cost less than gasoline

Explanation:

which division of the nervous system controls the radial muscles of the eye?

Answers

Answer:

sympathetic.

Explanation:

an adaptation of the epithelial cells of the proximal convoluted tubule for reabsorption is

Answers

Answer:

microvilli

Explanation:
having microscopic projections called microvilli. The epithelial cells of the proximal convoluted tubule are adapted.

The cells that have the general role of interacting with target cells and then inducing changes in them are ______.

Answers

The cells that have the general role of interacting with target cells and then inducing changes in them are called T-cells.

What do you mean by Target cells?

Target cells may be defined as a cell that is acted on selectively by a specific agent.

T-cells involve helper T cells (TH cells) and cytotoxic T cells (TC cells) which are represented by a cluster of differentiation CD4+ and CD8+ respectively.

Therefore, the cells that have the general role of interacting with target cells and then inducing changes in them are called T-cells.

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Nitrites are added to foods to: a. prevent formation of carcinogens. b. change their color. c. improve their nutritive value. d. inhibit rancidity. e. improve their texture.

Answers

Nitrites are added to foods to inhibit rancidity. These compounds are used in the food, chemical and pharmaceutical industries.

Nitrites are conservant that prevent the growth of Clostridium botulinum and Listeria bacteria.

These bacteria (Clostridium botulinum and Listeria) are harmful to human health, thereby nitrites must be added to foods.

In meats, nitrites also exhibit some other beneficial properties which include the pink color, antioxidant properties, and savory flavor.

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the mycelium is a mesh of filaments, each of which is called

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The mycelium is a mesh of filaments, each of which is called a hypha

nterphase lasts for ________ of a cell's life.

Answers

Answer: 12-24 hours

Explanation: Interphase generally lasts at least 12 to 24 hours in mammalian tissue. During this period, the cell is constantly synthesizing RNA, producing protein and growing in size.

Mendel knew that the variations in the offspring generations resulted from his experiments because he

Answers

Mendel was able to attribute the variation observed in the offspring of his experiment to the controlled fertilization process.

Mendel was able to control pollination and, thus, the fertilization process in the pea plants used for his experiment.

Mendel was able to effectively predict the outcome with self-pollination or cross-pollination with different results coming from each. Thus, he logically concluded that the variation observed in the offspring of his crosses is due to the fact that he controlled the fertilization process.

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When oxygen deprivation just prior to death turns off the brain's inhibitory cells, neural activity increases in the

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As oxygen deprivation just prior to death turns off the brain's inhibitory cells, neural activity increases in the VISUAL CORTEX. This brian region processes visual sensory information.

The visual cortex is a cortical brain region whose function is to receive, interpret and process visual sensory information.

The visual sensory information that is processed in the visual cortex comes from the eye retina, which has specialized cells (photoreceptors) to receive visual information.

The visual cortex is found in the posterior pole of the occipital lobe, and primarily in its medial region.

It has been shown that oxygen deprivation in the cerebral cortex can lead to cortical blindness.

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How does a cell know which genes to express.

Answers

The dominant alleles will always be expressed if there is at least one dominant allele in each gene. If there are no dominant alleles, the cell will express a recessive trait. The alleles’ dominance or recessiveness determines what gene is expressed.

Please, someone, help me with this asap!

Observe the cut ends of the flatworms using the hand lens or the dissection microscope immediately after cutting.
What do you see?
Are there distinct differences between the two ends?
Observe the cut ends of the flatworms over a period of several days. Do the flatworm halves continue to exhibit the same degree of difference that was seen right after they were cut in two?
What kinds of changes occur in the flatworms as they recover from having been cut in two?

Answers

The above question requires a personal answer about your experience with cutting flatworms. I can't tell you what you saw in this cut, but I'll show you what happens when it occurs.

First of all, you must understand that flatworms are worms with a great capacity for cell regeneration even if several pieces have been cut.

In this case, when a flatworm is cut in half, we can see the following events happen:

At the moment of cutting, the two ends of the flatworm body are equally shaped and are straight ends, without deformations.The ends will not be different if the cut is done accurately, but it may differ slightly.After several days, the ends will present some deformations and will lose the straight shape caused by the blade.Deformations are extremely similar and change similarly.When recovering from the cuts, each side of the flatworm body formed a new flatworm and they are no different, they are the same and they are completely recovered.

This is because the cellular regeneration of flatworms is very fast and allows any part of the flatworm's body to create exactly the same beings, as they have the same genetic makeup.

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white blood cells that engulf and destroy pathogens

Answers

There are 2 of them :-

1) Phagocytes

2) Macrophages.

These WBCs attach themselves to disease causing pathogens & then engulf them resulting in the destruction of the pathogens.

_________

Hope it helps!

꧁✿ ᴿᴬᴵᴺᴮᴼᵂˢᴬᴸᵀ2222 ✬꧂

is a wrong?..........​

Answers

Answer:

no it is correct I think hops it helps a lot;))))

No a is correct………………:))

Someone plz help me :(

Answers

I think A or B, depends what you feel about it

How can offspring be created that have a specific phenotype and genotype?

Answers

Explanation:

The two things a Punnett square can tell you are the genotypes and phenotypes of the offspring. A genotype is the genetic makeup of the organism. This is shown by the three genetic conditions described earlier (BB, Bb, bb). The phenotype is the trait those genes express. But when it comes to  apperences, a phenotype is an individual's observable traits, such as height, eye color, and blood type. The genetic contribution to the phenotype is called the genotype. Some traits are largely determined by the genotype, while other traits are largely determined by environmental factors.

Have an awesome day! :D

pls help im stuck on this question

Answers

Answer:

A- cellular respiration : carbon dioxide

Explanation:

This question is looking for byproducts ie Photosynthesis produces Oxygen. Cellular respiration produces Carbon Dioxide. Hopefully I was able to help you!

There are two types of reproduction, sexual and asexual Sexual reproduction involves two parents, while asexual reproduction only involves one,
Sort the reproductive processes below according to whether they are asexual or sexual.
ITEM BANK: Move to Bottom
Creation of an egg
Creation of fruit
Mushrooms producing spores
Production of seeds
Stem cuttings of plants
Sexual
Asexual
Budding in yeast
drag and drop answer here
drag and drop answer here

Answers

Creation of an egg- sexual

Creation of a fruit - sexual

Mushrooms producing spores - Sexual

Production of seeds - Sexual

Budding in yeast - Asexual

Stem cuttings of plants - Asexual

What is the two-layer membrane surrounding the nucleus that controls what materials go into and
out of the nucleus?

Answers

Answer:

Is the nuclear envelope.

Explanation:

The answer is D, the nuclear envelope.

Chemical to thermal to electrical current?Energy conversion of corn

Answers

Answer:

A battery is a device that converts chemical energy contained within its active materials directly into electric energy by means of an electrochemical oxidation-reduction (redox) reaction. This type of reaction involves the transfer of electrons from one material to another via an electric circuit.

Ciliated ependymal cells: A) help form the blood-brain barrier. B) circulate cerebrospinal fluid. C) form myelin in the brain and spinal cord. D) serve as wandering phagocytes during brain injury.

Answers

Ciliated ependymal cells: circulate cerebrospinal fluid.

Ependymal cells are a type of epithelial cell that is associated with the cavities of the body through which the cerebrospinal fluid circulates.

They are part of glial cells, which share space with neurons in the nervous system.

They create the membranes that keep cerebrospinal fluid circulating through the ependymal canal of the spinal cord and the cerebral ventricles.

For this, the ciliated structure that these cells present is essential for a correct movement of the cerebrospinal fluid, preventing it from spilling through other tissues and passing to areas of the body where it should not be.

The cilia move rhythmically creating tiny currents for fluid to flow through the central nervous system.

A small fraction of highly specialized and modified ependymal cells, called choroidal cells, are responsible for generating this essential fluid.

Therefore, we can conclude that ciliated ependymal cells circulate cerebrospinal fluid.

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Height in humans is a polygenic trait with a distribution similar to the graph shown. Which is true concerning the distribution of height in human populations?(1 point)


Most individuals will be below average height.

Most individuals will be at the extremes of height.

Most individuals will be of average height.

Most individuals will be above average height.

Answers

Answer:

Most individuals will be of average height.

Explanation:

Just took it and got 100%.

1. Which statement best describes a polygenic trait?

-A polygenic trait is controlled by multiple genes and influenced by the environment.

2. IQ is determined by:

-multiple genes and environmental factors

3. Which statement best describes trait distribution?

-Distribution describes how the variation in traits is spread across a population.

4. Which statement is true?

-Mendelian traits cannot be shown on a bell curve.

5. Height in humans is a polygenic trait with a distribution similar to the graph shown. Which is true concerning the distribution of height in human populations?

-Most individuals will be of average height.

Hope this helps have a good day and happy holidays!! ^^

which parts of the monomers involved in the dimer formation​

Answers

Answer:

A dimer (/ˈdaɪmər/) (di-, "two" + -mer, "parts") is an oligomer consisting of two monomers joined by bonds that can be either strong or weak, covalent or intermolecular. The term homodimer is used when the two molecules are identical (e.g. A–A) and heterodimer when they are not (e.g. A–B).

Explanation:

Which of the following can help lessen the effects of inherited peripheral neuropathy?

Answers

Answer:

d. All of the above

Explanation: is correct

It’s actually: there is nothing you can do

Do carbon dioxide molecules enter light dependent or light independent reactions from the atmosphere?

Answers

They enter light I dependent reactions

What are biological associations

Answers

Answer:

In ecology, a biological interaction is the effect that a pair of organisms living together in a community have on each other. They can be either of the same species (intraspecific interactions), or of different species (interspecific interactions).

Explanation:

pa brainliest

I was going to write the exact same thing the person above me wrote.

. Insulin controls the insulin level in ____________

Answers

Answer:

I dont really understand the question but if anything its the pancreas

Explanation: The pancreas produces insulin

Identify the organelles in the cell to the right.
А
חד
F
В.
А
B
С
с
C
D
E
F
E
DONE
D
plant cell

Answers

Answer:

A- Vacuole  

B- Chloroplast  

C- Cell membrane

D- Golgi bodies

E- Smooth and rough endoplasmic reticulum  

F- Cell wall

Explanation:

This is a structure of a plant cell which unlike animal cell has a cell wall as well as plasma membrane. It also contains large vacuoles present in the center of the cell. The green color of the plants is due to the presence of chlorophyll which is present in an organelles called chloroplast.

Organelles which are labelled in the cell are

A:Cell membrane

B:Vacuole

C:Nucleus

D:Cytoplasm

E:Chloroplast

F:Cell wall

The given figure represents a plant cell. So, the correct option is C.

What is Plant cell?

Plant cells are defined as eukaryotic cells that contain a true nucleus as well as specialized structures known as organelles that perform certain specialized functions. Plant and animal cells both contain a nucleus with similar organelles but plant cells differ due to the presence of a cell wall outside the cell membrane.

In the given figure, labelled organelles function are as follows:

Vacuole stores food, extra water, and waste while cell membrane permits selective passage of things into and out of the cell. The cell's nucleus serves as the activity's control centre, while the cytoplasm is the fluid that gives the cell its jelly-like consistency. Chloroplasts contain a substance called chlorophyll that is a green pigment that aids in photosynthesis. The cell wall of a plant gives it form, stiffness, strength, and protection.

Thus, the given figure represents a plant cell. So, the correct option is C.

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Your question is incomplete, most probably the complete question is:

Identify  the organelles in the cell to the right and label the parts A, B, C, D, E and F.

A.

A:Cell membrane

B:Vacuole

C:Nucleus

D:Chloroplast

E:Cytoplasm

F:Cell wall

B

A:Cell membrane

B:Vacuole

C:Nucleus

D:Cytoplasm

E:Chloroplast

F:Cell wall

C

A:Cell membrane

B:Nucleus

C:Cytoplasm

D:Vacuole

E:Chloroplast

F:Cell wall

D

A:Cell wall

B:Cell membrane

C:Nucleus

D:Cytoplasm

E:Chloroplast

F:Vacuole

why not test for pathogens like salmonella directly rather than use an indicator organism such as a coliform?

Answers

Indicator organisms are organisms that are utilized to detect the presence of another organisms that cannot be easily identified.

We do not test for pathogens like salmonella directly but use an indicator organism like coliform because these pathogens are not easily isolated and they are much harder to identify.

Pathogens like salmonella are not tested for directly because they are much lower in numbers when found in wastes or waterbodies and to identify them directly is expensive.

Also testing directly for these micro-organisms is very expensive and non-viable. So it is better to use indicator organisms to detect their presence.

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