In human males, the testes lie in the scrotum, because it helps in the

In human males testes lie in scrotum outside abdominal cavity. What will be the effect if testes fail to descend and remain in the abdomen?

In males testes are contained in the scrotal sacs because

Why are testes present inside the scrotum?

Why does testes lie in the scrotum outside the body cavity in human males ?