NEED HELP ON 17,18,19,20,21,22,23. ONLY IF YOU ARE POSITIVE ABOUT THE ANSWER

17. D. Chemical change

18. C. Cell wall

19. D. To transfer matter and energy within and between organisms.

20. A. Transporting materials

21. C. Carbon dioxide

22. A. Cellular respiration

23. C. Produce food and give off oxygen

Explanation:

I have been able to supply the correct answers. The cell wall functions as a structure that provides structural support and protection to the cell. It is tough, flexible and at times rigid. In a chemical change, new materials with new properties are manufactured. So, the process of photosynthesis is a chemical change.

The endoplasmic reticulum actually transports material. It transports materials like protein and lipids made within the cell and sends it to where they are needed.

Carbon dioxide  is the the gas that animals give off and plants use it during photosynthesis. Cellular respiration involves the activities that result to the breaking down of food in order to release energy.

because u need two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei to form isotopes.

so since they all have the same shape? i mean maybe because m& m and reeses are both chocolates