4. The purpose of having a light source on a microscope is to allow better viewing.
Energy which in turn produces the sugar the plant needs to go through photosynthesis
I think the answer is b or f
We breath oxygen because it is needed to burn fuel [ sugars and fatty acids] in our cells to produce energy. Oxygen is also brought into the lungs via breathing; where it is transported by red blood cells to the entire body to be used to produce energy. The food we eat gives us protein, sugars, vitamins etc. for energy
