Vestigial structures. These are structural elements that once served a purpose but as the organism evolved now serves no purpose.
The answer to this question is A. A simple Google search will help you find the answer. But, straightforward. That's what he stated in the document he made as the third law. So, that's the answer. Period.
Answer:
c
Explanation:
because it helps in chemical reactions
They obtain energy by consuming other organisms.
ATP molecules
Ig that what the question meant