To accurately answer your question, I would need to know what "part represented by A" refers to in your diagram of the animal cell. Normally, different parts of an animal cell are responsible for various functions.
- If "A" refers to the cell membrane, it would be "supports cell shape".
- If it is the mitochondria, then it would be "releases energy from food".
- If it is the nucleus, then it would be "controls cell activities".
- If it is ribosomes, then it would be "builds proteins".
If you provide more information about what part "A" is, I can give you the correct answer.