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.

Question: Metabolism is controlled by regulation of what? Answer: enzyme activity
8.5 Regulation of enzyme activity helps control metabolism.

Question: What is the connecting piece of a sperm packed with? Answer: mitochondria
The connecting piece of the sperm is packed with mitochondria. Mitochondria are organelles in cells that produce energy. Sperm use the energy to move.

Question: What is a solid particle that is indestructible? Answer: atom
Atoms are solid particles that are indestructible.