Which process must occur for a muscle to be able to relax?

A.
The amount of ATP in the neuromuscular junction must increase.
B.
A nerve must initiate an action potential in the muscle fiber.
C.
Myosin and actin must attach to each other.
D.
The concentration of calcium in the myofibril must decrease.

1. true.2. true.3. true.4. false.5. true.the concept of darwin's theory of evolution involves the idea that there are limited resources in a given living environment and that the organisms which live within have variations in their genetic make up due to random mating. the ones with beneficial genetic variations can express certain traits which give them an upper hand in surviving and reproducing in the said environment compared to ones who may have a more disadvantageous variation in traits. over time, the organisms with an upper hand will survive and reproduce more frequently and pass on their beneficial genes while the others die. the result is evolution, where we observe (usually, but not always) eventually, phenotypic distinct changes.