What has research taught us about sexual orientation? (write 800 words please)

Explain how paleontologists use trilobite fossils as index fossils for various geologic time periods.

When the oxygen produced by photosynthetic plants in the water dissolves in the water, which of these is being formed?

Internal feedback works to maintain homeostasis when your a. heart rate decreases as your white blood cells increase b. breathing rate decreases as your red blood cells decrease c. heart rate increases as your liver is cleaning blood d. breathing rate increases as your heart rate increases