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.

The concentration of calcium in the myofibril must decrease.

It's too short. Write at least 20 characters to explain it well.

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation:

for 8 am not sure maybe yes?

for 9 if it is asking if the male is more or less it would be less

hope i even just a little : )