Final answer:
Gorillas belong to grade 4, which includes apes and humans. They fall under the hominoid group and are classified within the genus Gorilla, part of the biological family Hominidae. The answer is option D.
Step-by-step explanation:
Gorillas are classified as grade 4 apes and man, indicating that they are part of the hominoid group, which includes gibbons, orangutans, chimpanzees, gorillas, and humans. These great apes are known for their lack of tails, larger size compared to other primates, and greater intelligence.
Specifically, gorillas belong to the genus Gorilla and are the largest of the hominids. They are part of the biological family Hominidae, which also includes chimpanzees, orangutans, and humans. There are just seven species within this family across four genera, with gorillas being native to Central Africa where the eastern and western populations are recognized as separate species, G. beringei and G. gorilla.