Christopher is an endurance athlete. He often gets low blood sugar during his long workouts. Once the liver recognizes the release of glucagon from the pancreas, is released to help increase his blood sugar levels

Glucose.

Explanation:

During periods of maximum efforts the heart pumps blood at 34 liters per minute, and this delivers oxygen to the muscles at 4 liters per minute. But this is insufficient to meet the oxygen requirement of the muscles. The pancreas produces insulin that changes the glucose to glycogen to maintain the body.

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.