During extended, intense exercise, a person begins to tire and breathe heavily. if this person continues to exercise, his muscles will soon switch from aerobic respiration to anaerobic (alcoholic) respiration anaerobic (lactic acid) respiration to aerobic respiration anaerobic (alcoholic) respiration to aerobic respiration aerobic respiration to anaerobic (lactic acid) respiration

Usually during exercise, unlike during rest times the muscle cells need to respire more. So they need more oxygen and glucose for energy and the carbon-dioxide produced as waste must be removed quickly. So when person gets tired or breathes heavily during intensive workouts means they are in need of more oxygen. So the cells starts performing anaerobic(lactic acid ) respiration even though it releases less energy.

hey, i believe your answer would be d. sugar ribose and the base uracil. i believe this is the answer, because rna consists of sugar ribose, adenine, guanine, cytosine, and uracil.

your first option is incorrect, because that's dna. where it consists of sugar deoxyribose, adenine, guanine, cytosine and thymine.

your second option is also incorrect, this is because sugar deoxyribose is in dna, and uracil is in rna. these two do not make sense together.

your third option being incorrect, because sugar ribose is in rna, but not the base of thymine. rna consists of uracil, not thymine.

lastly your fourth option being correct! this answer is correct, because both sugar ribose, and the base uracil are in rna! ~

answer is d. sugar ribose and the base uracil.