Step 1 : Introduction to the question "2. Which of the following South American animals is most closely related to the American alligator?"
...1. Abronia lizard 2. Green iguana 3. Black caiman 4. Turnip-tailed gecko All options all reptiles found in South America, but it is the caimans who belong to the family Alligatoridae whose only other family member is American alligators. There are several varieties of caiman, also spelt cayman, but the black caiman is the largest and can grow to lengths of 15 ft (4.5m). At one time this animal was very numerous but was hunted almost to the point of extinction for its valuable hide. The darker color of the black caiman absorbs heat as well as providing camouflage while this deadly carnivore is hunting. The other options are all smaller lizards found in the rainforests who are all fighting their own wars against loss of habitat.