Skeletal muscle fibers: a. Regenerate by mitosis into new fibers after gross injury b. Regenerate by satellite cells into collagen fibers after gross injury c. Regenerate by mitosis into collagen fibers after gross injury d. Regenerate by satellite cells into new fiber after gross injury

The correct answer is:

d. Regenerate by satellite cells into new fiber after gross injury

Here's why:

Skeletal muscle fibers do not regenerate through mitosis. Instead, they have a special type of cells called satellite cells. These cells are essentially stem cells for your muscles. When a muscle fiber is damaged, these satellite cells are activated. They start to divide and produce new muscle fibers to replace the damaged ones. This is how muscles repair themselves after an injury. So, the option that says "Regenerate by satellite cells into new fiber after gross injury" is the correct one.