Which of the following is a problem that resulted from the Green Revolution? A. Many countries that once had to import food now export food.
B. Pollen from genetically modified crops has entered organic farmland.
C. Areas that previously suffered from a lack of food now have higher food
production
O D. Many local traditional crop varieties have become threatened by extinction.

D. Many local traditional crop varieties have become threatened by extinction.

Explanation:

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.