After stimulation of ACh receptors, a muscle impulse spreads quickly along the and into the muscle fiber along T-tubules.

cancer   is   essentially   uncontrolled   mitosis   of specialized cells

which

what is a measurement of the earth’s history divided into time periods?

> fossil record <

sedimentary rock

> geologic time scale <

radioactive elements

they have identical fossils of organisms that have evolved over time.

both have animal fossils preserved in them due to weathering and erosion.

they contain different fossils because life on earth has changed through time.

the fossils in them were formed on the surface of earth due to exposure to sunlight.