Which of the following is a characteristic of an index fossil?
A.
The fossil is found only in an isolated part of the world.
B.
The fossil organism must have lived during a long span of Earth's history.
C.
The fossil must be found in great numbers.
D.
The fossil must look like many other fossils.

Answer:

cool

Explanation: yes cool

In the 1950s, Francis Crick and James Watson worked together at the University of Cambridge, England, to determine the structure of DNA. Other scientists, such as Linus Pauling and Maurice Wilkins, were also actively exploring this field. Pauling had discovered the secondary structure of proteins using X-ray crystallography. X-ray crystallography is a method for investigating molecular structure by observing the patterns formed by X-rays shot through a crystal of the substance. The patterns give important information about the structure of the molecule of interest. In Wilkins’ lab, researcher Rosalind Franklin was using X-ray crystallography to understand the structure of DNA. Watson and Crick were able to piece together the puzzle of the DNA molecule using Franklin’s data (Figure 9.2). Watson and Crick also had key pieces of information available from other researchers such as Chargaff’s rules. Chargaff had shown that of the four kinds of monomers (nucleotides) present in a DNA molecule, two types were always present in equal amounts and the remaining two types were also always present in equal amounts. This meant they were always paired in some way. In 1962, James Watson, Francis Crick, and Maurice Wilkins were awarded the Nobel Prize in Medicine for their work in determining the structure of DNA.

Photo in part A shows James Watson, Francis Crick, and Maclyn McCarty. The x-ray diffraction pattern in part b is symmetrical, with dots in an x-shape.

Figure 9.2 Pioneering scientists (a) James Watson and Francis Crick are pictured here with American geneticist Maclyn McCarty. Scientist Rosalind Franklin discovered (b) the X-ray diffraction pattern of DNA, which helped to elucidate its double helix structure. (credit a: modification of work by Marjorie McCarty; b: modification of work by NIH)

Now let’s consider the structure of the two types of nucleic acids, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). The building blocks of DNA are nucleotides, which are made up of three parts: a deoxyribose (5-carbon sugar), a phosphate group, and a nitrogenous base (Figure 9.3). There are four types of nitrogenous bases in DNA. Adenine (A) and guanine (G) are double-ringed purines, and cytosine (C) and thymine (T) are smaller, single-ringed pyrimidines. The nucleotide is named according to the nitrogenous base it contains.

(a) Each DNA nucleotide is made up of a sugar, a phosphate group, and a base.

Figure 9.3 (a) Each DNA nucleotide is made up of a sugar, a phosphate group, and a base.

(b) Cytosine and thymine are pyrimidines. Guanine and adenine are purines.

Figure 9.3 (b) Cytosine and thymine are pyrimidines. Guanine and adenine are purines.

The phosphate group of one nucleotide bonds covalently with the sugar molecule of the next nucleotide, and so on, forming a long polymer of nucleotide monomers. The sugar–phosphate groups line up in a “backbone” for each single strand of DNA, and the nucleotide bases stick out from this backbone. The carbon atoms of the five-carbon sugar are numbered clockwise from the oxygen as 1′, 2′, 3′, 4′, and 5′ (1′ is read as “one prime”). The phosphate group is attached to the 5′ carbon of one nucleotide and the 3′ carbon of the next nucleotide. In its natural state, each DNA molecule is actually composed of two single strands held together along their length with hydrogen bonds between the bases.

Watson and Crick proposed that the DNA is made up of two strands that are twisted around each other to form a right-handed helix, called a double helix. Base-pairing takes place between a purine and pyrimidine: namely, A pairs with T, and G pairs with C. In other words, adenine and thymine are complementary base pairs, and cytosine and guanine are also complementary base pairs. This is the basis for Chargaff’s rule; because of their complementarity, there is as much adenine as thymine in a DNA molecule and as much guanine as cytosine. Adenine and thymine are connected by two hydrogen bonds, and cytosine and guanine are connected by three hydrogen bonds. The two strands are anti-parallel in nature; that is, one strand will have the 3′ carbon of the sugar in the “upward” position, whereas the other strand will have the 5′ carbon in the upward position. The diameter of the DNA double helix is uniform throughout because a purine (two rings) always pairs with a pyrimidine (one ring) and their combined lengths are always equal. (Figure 9.4).

Answer:

Viviparity

Explanation:

Answer:

convergent evolution

Explanation:

Answer:Nothing would happen

Explanation:

Answer: Antibiotics are medicines used to prevent and treat bacterial infections. Antibiotic resistance occurs when bacteria change in response to the use of these medicines. Bacteria, not humans or animals, become antibiotic-resistant. These bacteria may infect humans and animals, and the infections they cause are harder to treat than those caused by non-resistant bacteria. Antibiotic resistance leads to higher medical costs, prolonged hospital stays, and increased mortality.

Explanation:

The major part in the earth system shows biosphere.

The areas of Earth where life is present are referred to as the biosphere. The biosphere encompasses everything from the deepest tree roots to the shadowy depths of the ocean, lush rain forests, and lofty mountaintops.

The areas of Earth where life is present are referred to as the biosphere. The biosphere includes the deepest tree roots, the shadowy depths of the ocean, lush jungles, and tall mountain peaks.

Earth is described by scientists as a sphere. The lithosphere is the Earth's solid surface layer. The air layer that rises above the lithosphere is known as the atmosphere. The hydrosphere is the collection of water on Earth's surface, below the surface, and in the atmosphere.

Therefore, The major part in the earth system shows biosphere.

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Answer:

The cell is the smallest structural and functional unit of living organisms, which can exist on its own. Therefore, it is sometimes called the building block of life. Some organisms, such as bacteria or yeast, are unicellular—consisting only of a single cell—while others, for instance, mammalians, are multicellular.

Explanation:

Answer:The cell is the smallest structural and functional unit of living organisms, which can exist on its own. Therefore, it is sometimes called the building block of life. Some organisms, such as bacteria or yeast, are unicellular—consisting only of a single cell—while others, for instance, mammalians, are multicellular.

Answer:

Animal should be bred once or twice per year.

Explanation:

their is interval of time where they get enough opportunity to rest and recover between pregnancies.

sorry if I'm wrong.

Your dog experiences a lot of pain throughout breeding, pregnancy, birth, and delivery. She needs all the time you can offer her to get over her trauma, animals should be bred once or twice per year, hence option c is correct.  

We advise giving her at least one heat cycle between each breeding, at the very least. Selective breeding is the process of controlling the breeding of organisms to either show or removes a certain trait.

Selective breeding makes use of artificial selection to direct the genetic transmission of desirable traits. In contrast to natural selection, selective breeding focuses on traits that will benefit humans. It is a technique that is widely used in plant management and animal husbandry.

Therefore, this selective breeding helps to obtain and retain the homozygous qualities of selected characters, animals bred once or twice per year rest and recover between pregnancies.

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Answer:

commensalism

Explanation:

A commensal relationship occurs when one species benefits from the close, prolonged interaction, while the other neither benefits nor is harmed.

Answer:

Your answer is A).

Explanation:

At terminal velocity, the weight of the object due to gravity is balanced by the frictional forces, and the resultant force is zero.

Answer:

Declining populations of phytoplankton, the basis of the marine food chain, will alter the seawater hues, potentially decimating fisheries. The world's oceans are warming and growing more acidic as a result of climate change, and a provocative new study suggests they'll be changing color too.

Explanation:

Hope this is good :)

The objects' mass, and The distance between the objects centers determines the strength of gravitational force.

The gravitational force is a force that attracts any two objects with mass. We call the gravitational force attractive because it always tries to pull masses together, it never pushes them apart.

This is called Newton's Universal Law of Gravitation. Admittedly, you don't have a very large mass and so, you're not pulling on those other objects much.

When the masses of the two objects are greater, there is a greater gravitational pull between them.

The separation between the centers of two objects affects their gravitational attraction to one another. The force is weaker the farther apart the items are from one another.

Therefore, The objects' mass, and The distance between the objects centers determines the strength of gravitational force.

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Answer:

UR supposed to answer how the tree of cells with the word bank

Explanation:

Answer:Am I the only one who doesn't understand the order

Answer: Duplication of chromosome can cause multiple genes to work in an uncontrolled manner.

Explanation:

There are numerous genes that are encoded by the chromosome. The duplication in the chromosome can cause multiple genes to go out of control that can cause patterning of the body and head which can influence the wing patterning or pigmentation. For example in Down's syndrome the three copies of chromosome number 21 are formed which is the trisomy of chromosome number 21 which can cause developmental issues in humans symptoms are flattened face, short neck, small ears, and others.

Answer with Explanation:

There's a fewer number of predators than prey because they are on the top level of the Food Pyramid. This means that they don't necessarily have to pass their energy to other organisms because only a few organisms consume them as compared to the "Primary Producers" like the phytoplankton and the algae, which support a large number of organisms above them.

The predators are more likely to receive also the least amount of energy compared to the organisms below the pyramid because as the energy is consumed as "food," only a portion of the food's energy is being passed to other organisms from one level to the other.

Answer:

The answer is C.

Explanation:

Over time knowledge changes, what might have been true back then isnt true now.

Answer:

Veins

1l carry blood from tissue of the body to the heart

2) are usually found closer beneath the skin

3) are less muscular then arteries

4) collapse if blood flow stops

arteries

1) carry blood back away from the heart to the tissue of the body.

2) found deeper within the body

3) are more muscular then veins

4) would generally remain open even if blood stops because of it's muscular structure.

Answer: I would agree

Explanation:

Answer:

your answer is NHA

Explanation:

I looked it up by asking what the three answers was and it gave me the question .

Answer:

a

Explanation:

Answer:

According to Chargaff's rule, if a DNA strand has 30% guanine before to semi-conservative replication, the  percentage of thymine that will have each new strand after replication will be 20% (option A).

Explanation:

A DNA molecule stores the genome of a living organism in a specific sequence of its nitrogenous bases adenine, guanine, cytosine and thymine. By knowing the percentage of a nitrogenous base in the DNA, the percentage of the other bases can be established using Chargaff's base pair rule.

Chargaff was able to establish that in a DNA molecule the ratio purine:pyrimidine is 1:1, so there must be the same amount of guanine as cytosine and a similar amount of adenine for thymine, taking into account the complementarity of the bases.

According to the base pair rule, if in a DNA strand there is 30% guanine, in the molecule there is:

In this case, Chargaff's rule is useful to determine the percentage of thymine that each new strand will have after replication, corresponding to 20%.

Answer: C

Explanation: This would actually have a negative effect, if we were to lower natural gas prices in the community, it would mean more usage of natural gas (a fossil fuel).

Answer:

Lowering Natural Gas Prices in the Community

Explanation:

took the test on a p ex