Lactic acid fermentation occurs in . .
a. any environment where oxygen is present.
b. yeast cells.
c. the mitochondria of plant cells.
d. muscle cells.

the answer is D} Muscles

when our muscle cells are not receiving enough oxygen they switch to a mode producing Lactic Acid fermentation.

burning fossil fouls really decrease the carbon in the atmosphere so b

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.