The diagram below illustrates the change that occurred in the physical appearance of a rabbit population over a 10-year period.
Original Fur Colors
Fur Colors 10 Years Later
4. Explain how the rabbit population evolved.

these muscles maintain the blood pressure in the vessels. the smooth muscles are innervated by nerves of the autonomic nervous system. when the muscles contract, they cause vasoconstriction of the vessels and increase blood pressure. when the muscles relax, they enable vasodilation of the   blood vessels hence reduce blood pressure.