Question

question 29
lactic acid build up in muscles is a sign that
aerobic respiration capacity has not been reached
respiration is operating effectively
fermentation is occurring
the muscles will be able to operate continuously

Explanation:

Lactic acid is produced during lactic acid fermentation. When oxygen is limited (such as during intense exercise), muscle cells switch from aerobic respiration to fermentation. Aerobic respiration capacity being reached would lead to fermentation (and lactic acid build - up), not the opposite. Respiration operating effectively usually refers to aerobic respiration which does not produce lactic acid. Lactic acid build - up causes muscle fatigue and does not allow continuous operation.

Answer:

fermentation is occurring