The layer of the atmosphere where most of the weather happens is called the troposphere.
The answer is A. Nucleus-forms peptide bonds
A
it says the swallows had Continued reduced reproductive success over time.
Answer:
C
Explanation:
the first 2 choices aren't even systems at all, and D is specifically talking about the water and not mentioning animals/plants at all.
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Answer:
B. a nucleus
Explanation:
cell walls and chloroplast are both found in plant cells, not in animal cells
