Because it has to be that way
The answer is B. The planets were all formed from dust that was orbiting around the sun.
<span>Water heats up, changes to water vapor and evaporates, rises into the sky. It cools, condenses, turns back into liquid water forming clouds. Then it falls back to earth as precipitation and runs down hills or mountains during runoff and returns to lakes and oceans.
I think i`m not sure :)</span>
My best guess would be c because b makes no since we as humans do not have photosynthesis and are considered living organisims, d is also wrong because the brain requires oxygen, and its not a because the brain is made of cells.