During fermentation, yeast cells convert pyruvate to ethanol and CO2. Fermentation also occurs in human muscle cells when oxygen is depleted. In the case of muscle cells, what are the by-product(s) of the fermentation of pyruvate?1. Oxygen and ATP2. Ethanol and Co23. Lactic acid 4. Sugar and protein5. ATP and NADH

option 3 lactic acid

Explanation:

In the muscle cell, during strenuous exercises, the oxygen cannot be taken to the respiratory system fast enough to allow for aerobic respiration to occur. thus, for continuous production of ATP, the muscle cell have to reduce pyruvate in the process of lactic acid fermentation to give rise to Lactic acid, ethanol and carbondioxide. this way, the cell can continue to produce ATP but in low amounts compared to aerobic respiration, although accumulation of lactic acid can lead to muscle fatigue and pain.

chordata is the answer

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: