During a warm up increased body and muscle temperatures promote increases in?

Flexibility and extensibility.

A warm-up prepares the muscles for physical activity by increasing blood flow, oxygen delivery, and promoting elasticity and flexibility. As muscle and body temperature rise during a warm-up, the viscoelastic properties of muscles change, making them more pliable and capable of greater extension and contraction. This increased extensibility reduces muscle stiffness, improves range of motion, and lowers the risk of injuries during subsequent intense or strenuous physical activities.