1. which of the following is a biotic factor?

a. sunlight
b. worms
c. water
d. climate

2. nitrogen is used by

a. plants
b. animals
c. both a and b
d. neither a or b

3. as you move from level to level in an energy pyramid, energy

a. decreases
b. increases
c. stays at the same level
d. is destroyed

4. the part of earth that supports life is a(n)

a. biome
b. ecosystem
c. biosphere
d. organism

5. population can be even, random, or clumped together.

Drag each tile to the correct box. the body monitors the levels of oxygen in the blood to regulate breathing. isabel is running in a marathon and is near the finish line. she feels out of breath. how will her nervous system work to generate a reaction? arrange the tiles in chronological order. isabel's breathing rate increases. sensory receptors in the arteries detect low oxygen levels. the brain sends signals through motor neurons. sensory neurons generate an impulse. the central nervous system relays an impulse to certain brain regions.