The outer coverings that are tough but, flexible provided protection to the land plants.
Together organ systems make us healthy and living.
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".
They check for mistakes and bias
