A). Explain the meaning of the term gas exchange surface in human lungs. b). List three features of gas exchange surfaces.

c). Explain how each feature in your list helps gas exchange to happen efficiently.

Cells destroy body cells infected by a virus or bacteria.

Which of the following best describes the expensive tissue hypothesis? brains require more energy, so the gut had to be reduced, and larger brains and tool use led to higher quality diets. increasing body size means that homo neanderthalensis had to include more fat in its diet. brains require more energy, so the gut had to be reduced as brains got bigger. brains require more fat, so the gastrointestinal viscera (gut) had to expand, and hands were needed to acquire more food.

The term facultative anaerobe refers to an organism that