I'm almost 100% it is the first option
Provided that there's no diagram, most molecules have particular areas on the molecules, called the "active area" that act as a lock to a particular substrate's molecular structure, providing the key.
An enzyme's active area is only able to be "unlocked" by a certain substrate's "key".
Answer:
The color of the surfaces because an object with a black surface will absorb and reradiate energy faster and at a higher concentration than the same object with a lighter colored surface.
Answer:
The moons gravity pulls on the water :)
