Answer:
Step-by-step explanation:
Plants use both photosynthesis and cellular respiration to generate energy because they have organelles called chloroplasts that enable them to carry out photosynthesis. Chloroplasts contain chlorophyll, which allows plants to convert light energy into chemical energy in the form of glucose.
However, photosynthesis only occurs during the day, when there is sufficient light available. At night or in the absence of light, plants still need to generate energy to carry out cellular processes, such as growth, repair, and reproduction. This is where cellular respiration comes in.
Cellular respiration is the process by which cells break down glucose to generate energy in the form of ATP (adenosine triphosphate). Unlike photosynthesis, which only occurs in plants and some bacteria, cellular respiration occurs in all living organisms, including plants, animals, and microorganisms.
Animals only use cellular respiration to generate energy because they do not have chloroplasts and cannot carry out photosynthesis. Instead, they obtain energy by consuming other organisms, either directly or indirectly. The food they consume contains organic compounds, such as carbohydrates, proteins, and fats, which are broken down during cellular respiration to generate ATP.
In summary, plants use both photosynthesis and cellular respiration because they have chloroplasts that enable them to generate energy from sunlight during the day, while also using cellular respiration to generate energy at night or in the absence of light. Animals, on the other hand, only use cellular respiration because they do not have chloroplasts and cannot carry out photosynthesis.