In c4 and cam plants carbon dioxide is fixed in the of mesophyll cells.

some inherited genetic mutations can be good for the offspring, so the answer is different genetic mutations cause many forms of cancer.

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.