I think the correct answer is receptor. To respond to a chemical signal a cell must have a receptor and also this where the signaling molecule can bind. A receptor is a protein molecule that can receive signals from the outside environment of the cell.
The answer is D. A turtle suns itself on a rock during a cool day
Differential reproduction means that some organisms in a population produce more offspring than others.
Differential reproduction refers to the difference between individuals in a population and how many offspring they are able to leave.The best adapted organisms to a given environment will leave more offspring than those who are not well adapted. Differential reproduction depends on the natural