Normal development in tests requires a temperature. cremaster muscle contract or relax to move testes toward or away from the body or to maintain the acceptable temperature for testicular.
The body temperature regulation is controlled by the autonomic nervous system under the guidance of medulla oblongata which is in the brain system.
The biceps and triceps muscles work together to allow you to bend and straighten your elbow. When you want to bend your elbow, your biceps muscle contracts (Figure below), and, at the same time, the triceps muscle relaxes. The biceps is the flexor, and the triceps is the extensor of your elbow joint.
I believe the answer is C, hope this helps!
