One difference between mitochondria and chloroplasts is A)
mitochondria use NADH while chloroplasts make NADH.
B)
mitochondria produce water from oxygen while chloroplasts produce
oxygen from water.
mitochondria are only found in animal cells and chloroplasts are only
found in plant cells.
the Calvin cycle occurs in the mitochondria while the Krebs cycle occurs in
the chloroplasty
D)

B: mitochondria produce the water from oxygen and the chloroplast produces oxygen from water.

Explanation:

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link:

organ system-an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.