Can someone please help me i am in need of some assistance Which statement best describes the role of lichens in ecological succession?

A. They replace smaller trees and shrubs that need less sunlight.

B. They add nutrients to the soil and hold the soil together with roots.

C. They release acids that help break down bare rock to form soil.

D. They use nitrogen from the air to make nutrients that plants can use.

phylogenetic tree is the tree of life or evolution tree. it shows the different branches of evolution. the sequence goes like tissues - coelom - backbone - endoskeleton - segmentation

make   gliitsh plesea   !

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.