how has the skeleton of a frog modified for jumping?

Answer 1

The frog skeleton is adapted for jumping, and has a well-developed pair of hindlimbs, and a special structure, the urostyle, which represents a number of fused caudal (tail) vertebrae. The urostyle is capable of withstanding stress transmitted to the vertebral column from jumping. Notice that the vertebral column is short and inflexible, so it does not bend during jumping.

The femur and tibiofibula are both long bones which are important for jumping. The tibiofibula represents a fusion of two bones, the tibia and the fibula; this fusion results in a stronger structure. The humerus and radius/ulna are not as elongate as the bones of the hindlimb, since they do not provide the major propulsive force in frog locomotion.♥

Answer 2

Skeleton Frog

Answer 3

Very simple: it never modified, frogs were created like that.