Answer:
For example, the biceps muscle, in the front of the upper arm, is a flexor, and the triceps, at the back of the upper arm, is an extensor. When you bend at your elbow, the biceps contracts. Then the biceps relaxes and the triceps contracts to straighten the elbow.
Stars are formed in clouds of dust and gas (nebulae.) Nuclear reactions at the center (core) of stars gives enough energy to make them shine brightly for many, many years. The exact l<span>ifetime of a star depends on its size.</span>
Answer:
B. They are both necessary for organisms to survive
Explanation:
organisms rely on both living and non-living factors to survive.
Ex: An orange tree needs worms, birds, and insects to keep it alive and to plant more trees and it needs dirt and water.
