Answer:
A- cellular respiration : carbon dioxide
Explanation:
This question is looking for byproducts ie Photosynthesis produces Oxygen. Cellular respiration produces Carbon Dioxide. Hopefully I was able to help you!
B. Arteries have a thicker tunica media than veins
That would be the Compound Microscope, it provides a high magnification that can visibly see movement in the cell, however, it has a low resolution. Hope it Helped!