How does the absence of neck help the frogs to survive?

In frogs, the neck is missing, and the head continues directly into the trunk. 
The frog rests on land with its small forelimbs upright and its long hind limbs folded in a Z shape. The frog jumps by extending its hind limbs abruptly, as though flinging springs. 
The frog's ability to jump is aided by the lack of a neck.