I believe step 4, because in mitosis it creates 2 diploid cells
Chloroplasts;
These contain grana, the site of the light-dependent reaction of photosynthesis, and stroma, a fluid substance that is the equivalent of cytoplasm in cells, which is the site of the light-independent reaction of photosynthesis. Grana are structures made of stacked thylakoid membranes, necessary for chemiosmosis, connected to one another by lamellae.
I think you just answered your question. They encourage adolescents to eat calcium-rich foods because it aids in bone formation, like you said.
