Answer: C
Explanation: Left ventricle. With the thickest muscle mass of all the chambers, the left ventricle is the hardest pumping part of the heart, as it pumps blood that flows to the heart and rest of the body other than the lungs.
The answer is concentration gradient. Have a good day.
D ribosomes because it makes the energy for the cells
Wavelengths is the possibly correct answer also it’s on study island