Which organism would be the best subject for a study of both photosynthesis and cellular respiration?

a green plant

a chemosynthetic bacterium

an animal that eats plants

an animal that eats animals

The best answer should be a green plant. That is because animals cannot photosynthesize. Chemosynthetic bacterium like cyanobateria can't respire, even though they do photosynthesize like plants. Plants can do both as they are autotrophs, while animals are consumers. The green in them enables them to photosynthesize.