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3 years ago

Why copes ideas about the evolution of tetrapods were considered a hypothesis and not a theory

1 answer:

8 0

Cope's Rule postulates that animal groups tend to evolve through time towards larger body size. Even though larger body size is often advantageous trait it isn’t always that way (larger organisms require greater amount of food, and can have problems when food is sparse).

But this postulate isn’t theory, because body size increase through time, but the mean body size often doesn’t.

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Cho các nhận định về sinh sản vô tính. Nhận định không chính xác là

artcher [175]

Answer:

what

Explanation:

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3 years ago

Even though streams that flow through valleys generally move very fast, the stream load is

mihalych1998 [28]

Answer:

Explanation:

The gradient in bed load is mostly made up mostly of gravels and sands, broken down versions of larger boulders and rocks, which are most commonly found in mountainous areas. Streams with low gradients cannot carry bed load down stream because it moves slowly and without much force. Gravels and sands couldn't move downstream because the water flow isn't strong enough to move them or to keep them in motion.

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3 years ago

In the alveolus pictured above, a disease or

Inessa [10]

<h2><u>Full Question:</u></h2>

In the alveolus pictured above, a disease or injury to which structures would reduce the ability of oxygen to diffuse from the alveolar space to the capillary?

A. A and B

B. B and C

C. B and D

D. A and D

<h2><u>Answer:</u></h2>

The correct answer is option D.

<h3><u>Explanation:</u></h3>

Alveoli is defined as the unicellular thickened sac like structure of lungs which helps in exchange of gases in lungs. The exchange membrane of lungs comprise of three structures -

A. The epithelium cells of Alveoli,

B. The basement membrane of alveolar epithelium,

C. The endothelial layer of blood capillary.

The red blood cells described here won't cause any problems to the diffusion of gases from alveolar cavity to blood. The structures mentioned here as the type 2 cells of Alveoli which secrete lecithin, a surfactant which releases the surface tension of Alveoli. This compound prevents the Alveoli from collapsing and helps in diffusion of gases. The other structure mentioned here as D are the alveolar epithelium which is the unicellular thickened membrane of Alveoli, helping in gaseous exchange.

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3 years ago

Consider two mammalian cells, one in G1 and the other in G0 (stationary) phase. If they are stimulated to pass the restriction p

Kamila [148]

Answer:

A, Both cells will replicate their DNA.

Explanation:

During the cell division, cell passes through several phases and divides. Before each phase, the cell has to pass through the checkpoints. At these cell checkpoints, the cell receives the internal and external signals.

When the cell is arrested at G₀ phase, the cell does not divide until it receives a signal to proliferate but when the cell passes the G₁ phase, the cell will divide continuously.

In the given question, if the cells when in their G₀ and G₁ phase receive proliferation signal, the G₀ phase cell will also divide and will replicate it DNA during S phase as G₁ phase cell will do.

Thus, Both the cells will divide their genetic material.

8 0

3 years ago

Tim and Jan have freckles but their son Mike does not have. Show with a punnete square how this is possible. Tim and Jan have tw

Snowcat [4.5K]

Answer:

Parents are heterozygous for the trait, and this is how they got a child with no freckles.
The probability that the two other children will have freckles is 9/16

Explanation:

Due to technical problems, you will find the complete explanation in the attached file.

Download pdf

8 0

3 years ago