In skeletal muscle, the sarcoplasmic reticulum stores a very high concentration of ca++. when ca++ is released into the cytosol of muscle to facilitate contraction, it needs to be removed and pumped back into the sarcoplasmic reticulum so that skeletal muscle can return to its relaxed state. the ca++ is moved from cytosol and pumped back into the sarcoplasmic reticulum where its concentration is much higher. what type of membrane transport does this represent?

Primary active transport.

Explanation:

Active transport may be defined as the movement of particles against the concentration gradient. This is the energy driven process that requires ATP to transport the molecules.

Two main types of active transport are primary active transport and secondary active transport. The calcium has been moved towards its region of higher concentration ( sarcoplamsic reticulum) from its region of lower concentration (cytosol), this transport is against the concentration gradient. The ATP is used by direct hydrolysis. Hence, it is the primary active transport.

Thus, the answer is primary active transport.