Question

question 49
the contractile unit of a muscle is the
sarcolemma
sarcomere
motor end
muscle fiber
question 50
a specific activation must be reached for muscle activation to occur.
question 51
a muscle is needed to determine muscle fiber type

Explanation:

Question 49: The sarcomere is the basic contractile unit of a muscle. It contains actin and myosin filaments that slide past each other during muscle contraction.
Question 50: A threshold of activation must be reached for muscle activation to occur. This is related to the electrical and chemical processes that initiate muscle - fiber contraction.
Question 51: A muscle biopsy is often used to determine muscle fiber type. By examining the tissue under a microscope, different fiber types (such as slow - twitch and fast - twitch) can be identified based on their characteristics.

Answer:

Question 49: Sarcomere
Question 50: Threshold
Question 51: Biopsy