Plz help! question 1)
how does the pleura help with breathing?

question 2) what is the purpose of the diaphragm?

Biology!

1.The pleural cavity aids optimal functioning of the lugs during breathing. It transmits movements of the chest wall to the lungs, particularly during heavy breathing. The closely approved chest wall transmits pressures to the visceral pleural surface and hence to the lung (10-19.

2.The diaphragm, located below the lungs, is the major muscle of respiration. It is a large, dome-shaped muscle that contracts rhythmically and continually, and most of the time, involuntarily. Upon inhalation, the diaphragm contracts and flattens and the chest cavity enlarge.

Explanation:

i think it would be b. tissue because an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.