Answer:
The Respiratory system allows the entry of oxygen into the body and releases Carbon Dioxide. The Oxygen travels across lung tissue into blood vessels and the blood carries the oxygen around the body. Thus the Respiratory and Circulatory systems work together in gas exchange which is vital in Homeostasis.
Most stomata are located on the bottom of leaves because direct sunlight does not hit the bottom surface. If stomata were on the upper epidermis (the top side of the leaf), the direct sunlight hitting the leaf would cause more water to be lost through the stomata because of evaporation. Hope this helps!