The substrate and the active site both need to fit together perfectly in order for the enzyme to work properly. If their shape is changed, typically through heat or a change in pH, the enzyme will not work.
Answer:
Oxygen was not present on early earth
It would be easier to put an image instead of explaining it. Here you are!
R = Red
r = white
RR = 25% - 25% chance of red
Rr = 50% - 50% chance of pink
rr = 25% - 25% chance of white
Explanation:
Well, its extremely hot in the hydrothermal vents. Scientists simply believed it would be impossible for anything to survive due to the heat. Bacteria and micro-organisms were able to adapt to growing there, though. So in short words, they survived extreme conditions teaching scientists that life was quite adaptable.
Weird fun fact: In Switzerland it is illegal to own just one guinea pig. Felt the need to mention that ^ Sorry, I know it has nothing to do with the question but i felt it was worth speaking of.