The cheetah seems to be headed for extinction because, resulting from intensive inbreeding generations ago, the species has so little genetic variation that it is extremely vulnerable to environmental change. (A) because, resulting from intensive inbreeding generations ago, (B) because, as a result of intensive inbreeding generations ago, (C) because they inbred intensively generations ago so that (D) because there was intensive inbreeding generations ago and (E) as a result of their intensive inbreeding generations ago.

Answer: E) as a result of their intensive inbreeding generations ago.

Explanation: Cheetahs face difficulties in reproduction and are susceptible to viruses because they are genetically too similar. Mating between close relatives is the main reason for the threat of extinction that cheetahs face.

The cheetah is a unique felid, with its closest living relatives being the puma and jaguarundi of the Americas. This cat is notable for modifications in the species' paws, being one of the few felids with only semi-retractable claws.

Almost every facet of the cheetah's anatomy has evolved to maximise its success in the chase, the result of an evolutionary arms race with its prey. Due to this specialisation, however, the cheetah is poorly equipped to defend itself against other large predators, with speed being its main means of defence.