Why is it important that cardiac muscle tissue does not tire? A. Cardiac muscles are voluntary muscles and they control your heartbeat.
B. Cardiac muscle cells are not striated and they control your heartbeat.
C. The heart must absorb nutrients to keep you alive.
D. The heart must beat repeatedly to keep you alive.

It is important that cardiac muscle tissue does not tire so that a continuous supply of Oxygen to the tissues is maintained. Otherwise, the metabolic activities of the body will cease. Cardiac muscles are the muscles of the heart.

Explanation:

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its weight is greatest on earth

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.