Action potential propagation in a skeletal muscle fiber ceases when acetylcholine is removed from the synaptic cleft. which of the following mechanisms ensures a rapid and efficient removal of acetylcholine? a) acetylcholine is degraded by acetylcholinesterase. b) acetylcholine is transported back into the axon terminal by a reuptake mechanism. c) acetylcholine is transported into the postsynaptic neuron by receptor-mediated endocytosis. d) acetylcholine diffuses away from the cleft.

a) Acetylcholine is degraded by acetylcholinesterase.

Explanation:

After it binds for its receptor on the plasma membrane of the postsynaptic cell, acetylcholine must be removed in order to prevent repeated stimulation. Acetylcholinesterase is enzyme for the inactivation of acetylcholine, present at all cholinergic synapses. This enzyme hydrolyses acetylcholine and breaks it to the acetate and choline. Choline can be reused for the synthesis of the new acetylcholine molecule so it is taken back into the presynaptic cell.

answer: grassland biomes are closer to the equator and receive more rain.

grasslands are biomes that are dominated by grasses rather shrubs and trees. savanna are biomes that exhibit grasses, shrubs and small tree as vegetation. grasslands are located near the equator of the earth. these are found in north america. savanna biomes are found in africa, south america, australia and india. grassland exhibit moderate climatic conditions, it receives   amount of rainfall higher than savanna.   therefore, savanna exhibit dry and hot climatic conditions.