I attached an answer that I found, but I'm not sure.
The muscular system can be broken down into three types of muscles: skeletal, smooth and cardiac, according to the NIH. Skeletal muscles are the only voluntary muscle tissue in the human body and control every action that a person consciously performs. The muscle that is found at the heart is Cardiac Muscle. It is an involuntary, striated muscle that constitutes the main tissue of the walls of the heart. Hope this helps.
Answer:
Oxygen was not present on early earth
Answer:
I believe there are 6
Explanation:
Protons are the positively charged circles (blue)
Neutrons are the Neutral (red)
and the others (green) are called electrons
