Given the task definition and input, reply with output. Given a scientific passage and an answer, generate a question for the given answer.

Passage: Variation in muscle cells gives further insight into some benefits of anaerobic respiration. In vertebrate muscles, lactic acid fermentation allows muscles to produce ATP quickly during short bursts of strenuous activity. Muscle cells specialized for this type of activity show differences in structure as well as chemistry. Red muscle fibers are "dark" because they have a rich blood supply for a steady supply of oxygen, and a protein, myoglobin, which holds extra oxygen. They also contain more mitochondria, the organelle in which the Krebs cycle and electron transport chain conclude aerobic respiration. This is endurance muscle. White muscle cells are "light" because they lack the rich blood supply, have fewer mitochondria, and store the carbohydrate glycogen rather than oxygen. This is muscle built for sprinting. Answer: anaerobic
Variation in muscle cells gives further insight into some benefits of what type of respiration?