Tag: biology

• Like animals, plants also respire all the time because their cells need energy, to stay alive, but plants can only photosynthesize when they are in the light. Photosynthesis happens in the chloroplasts of plant cells. 
• It produces glucose for use by the plant, and oxygen as a waste product. Respiration uses oxygen and produces carbon dioxide and water as a waste product.
  

Oxygen is a waste product of photosynthesis. While carbon dioxide is exhaled by the plants at night in absence of photosynthesis. Excess water is given out by transpiration.
So the answer is- all of these.

Plants eliminate some waste through diffusion. During the day, excess oxygen gas produced by photosynthesis is released through the stomata. Carbon dioxide produced by respiration is normally used up during photosynthesis. At night, however, as photosynthesis slows, carbon dioxide is not used up as fast as it is produced, and it is released as a waste product. Plants also release waste water by transpiration and guttation. 

Plants eliminate some waste through diffusion. During the day, excess oxygen gas produced by photosynthesis is released through the stomata. Stomata are microscopic pores in leaves. Carbon dioxide produced by respiration is normally used up during photosynthesis. At night, however, as photosynthesis slows, carbon dioxide is not used up as fast as it is produced, and it is released as a waste product. Plants also produce oxygen as a by-product of photosynthesis. The oxygen that is not used for respiration is also excreted through the stomata. Plants do not excrete gases through flowers, roots and seeds.