The answer to this question is D
.
Answer:
common ancestor. ... Mammals share the homologous structure of the vertebrae in common.
Explanation:
Answer:
Fracking can contaminate water supplies if it is not done properly, because the fracking fluid injected into rock to enable gas to be released often contains chemicals. If the borehole is not properly cased to stop leaks, the fracking water can escape into the aquifer
