The Answer is C Gas exchange take place in our lungs
Photo Synthesis would be as plants grow from the sun or gain energy from the sun, where as Cellular Respiration is when cells divide into two or more. (I believe)
They release the gas Oxygen.
Explanation:
Combine like terms.
-2y + 7y = 5y
-4 - 5 = -9
So the answer would be <u>5y - 9</u>