Given a scientific question and its correct answer, generate supporting facts for the answer. This supporting fact can be an explanation for the answer to the given question.

[Q]: Question: What are the building blocks of peptides? Answer: amino acids
[A]: A peptide is composed of two or more amino acids. Amino acids are the building blocks of peptides.

[Q]: Question: What do you call vesicle transport into the cell? Answer: endocytosis
[A]: Vesicle transport into the cell is called endocytosis. The cell membrane engulfs the substance. Then a vesicle pinches off from the membrane and carries the substance into the cell.

[Q]: Question: When hit from behind in a car crash, a passenger can suffer a neck injury called what? Answer: whiplash
[A]:
When hit from behind in a car crash, a passenger can suffer a neck injury called whiplash . Explain in terms of inertia how this occurs, and how headrests can prevent the injury.