What is the most important muscle involved in breathing? *
a. Bicep
b. cardiac
c. Gluteus maximus
d. Diapragm

D. Diaphragm

Explanation:

The work of breathing is done by the diaphragm, which is the muscle between the ribs, the muscle(s) in the neck and the abdominal muscles, the diaphragm itself is a sheet of muscle that is the shape of a dome, it separates the chest cavity from the abdomen, and is the most important muscle used for breathing

Hope this helps

Have a nice day((:

The answer is D. The scientific method involves developing a question to answer a hypothesis. It has to determine whether a hypothesis is true or not which would involve questions that can be answered through testing and observation of the subject.