If the length of the absolute refractory period in cardiac muscle cells was the same as it is for skeletal muscle cells,
a) it would be much longer before cardiac cells could respond to a second stimulation
b) contractions would last as long as the refractory period pacemaker cells would cease to spontaneously depolarize
c) tetanic contractions might occur, which would stop the heart's pumping action

Answer is C. Tetanic contraction might occur which would stop the heart's pumping action.

Explanation:

Tetanic contraction occurs when the muscle fiber doesn't fully relax before it contracts again due to repeated stimuli at short intervals.

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:

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