Answer:
The correct answer is "a green plant".
Explanation:
Green plants are multicellular eukaryotic organisms widely known for their roles as producers in the food chain. Green plants produce their own food in the process known as photosynthesis, at which green plants use sunlight to transform carbon dioxide into chemical energy in the form of glucose. Green plants also perform cellular respiration, the process at which glucose is further processed to produce ATP, the molecular currency of energy. Since green plants can perform both photosynthesis and cellular respiration, they are the best subject to study these biological processes.
