The answer is quite simple, Photosynthesis and metabolism.
I believe b is the correct answer
Tobias drank from a contaminated water fountain
You have to first make some observations and then ask a question. Then you make a hypothesis (or guess) what the answer is - do the experiment to see if you're right!
While both will equate changes in a genetic chain, deletion would have more severe consequences. A substitution mutation usually only causes minor disorders and diseases, like sickle cell anemia. Whereas deletion causes much more serious diseases, like cystic fibrosis, and turner syndrome which is where a female is born with only one X chromosome.
