<h3><u>Answer;</u></h3>
B
<h3><u>Explanation;</u></h3>
- Smooth muscle is found in the walls of hollow organs throughout the body.
- Smooth muscle contractions are involuntary movements triggered by impulses that travel through the autonomic nervous system to the smooth muscle tissue.
- <u>The smooth muscle of the alimentary canal or the digestive tract facilitates the peristaltic waves that move swallowed food and nutrients.</u>
Answer:
The answer should be C
Explanation:
If you look at the the graph, C points to the time period after mammals appeared. Since birds are mammals, they should have appeared after the time that mammals first came to be on Earth.
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Answer:
The correct answer is option b. "20 H1, 40 H2A".
Explanation:
Chromatin is a complex that protects and condenses the genetic material comprised of DNA and proteins. When chromatin is in the form of a 30 nm fibril, nucleosomes have a regular positioning along the DNA. This means that each nucleosome is associated with a single H1 molecule. Therefore a chromatin containing 20 nucleosomes will have 20 copies of H1 and 40 copies of H2A, because each nucleosome has 2 copies of the core histone H2A.