1. humans
   gorillas
2. chimpanzees

Gorillas are the largest members of the primate family.

1. chimpanzees
   orangutans
2. tarsiers

Great apes include chimpanzees, bonobos, gorillas, orangutans and humans.

1. Apes have opposable thumbs; monkeys do not.
   Monkeys have tails; apes do not.
2. Apes walk upright; monkeys walk on all fours.

The easiest way to distinguish monkeys from apes is to look for a tail. Most monkey species have tails, but no apes or hominids do.

1. the size of the gorilla population
   the whereabouts of poachers
2. the gorilla's level of health

The number of gorilla nests gives an approximation of the population size. Also, researchers can extract hair samples from these nests in order to examine individuals' health.

1. to conserve energy
   to hunt
2. to use tools

In an experiment, humans used 75 percent less energy walking upright than chimps used walking on all fours. Essentially, walking upright seems to be beneficial because it saves energy.

1. 75 percent
   83 percent
2. 96 percent

Chimpanzees are humans' closest genetic relatives, sharing around 96 percent of the same DNA sequencing.

1. Chimpanzees can learn human language.
   Chimpanzees use tools.
2. Chimpanzees split from humans around 4 million years ago.

Goodall's work with chimpanzees in Gombe, Tanzania, documented the apes using tools to complete or simplify tasks like cracking nuts open

1. gorillas
   orangutans
2. chimpanzees

Orangutans are the only great apes native to Asia.

1. age
   geography
2. diet

Old World monkeys are found in the Eastern Hemisphere, while New World monkeys are found in the Western Hemisphere.

1. France
   Germany
2. Spain

The Spanish parliament voted in June 2008 to support the tenets of the Great Ape Project. The nonprofit organization lobbies on behalf of great apes (chimps, gorillas, bonobos and orangutans) for their right to life, protection of individual liberty and prohibition of torture.