How does water enter the area marked with an a?

The water can enter the area marked with an A through rainfall that hits the Earth's surface and  a runoff flows across the surface, then most of this water soaks into the ground and seeps down to become groundwater and flow along until it will reach the river, lake or ocean.

1. what is the relationship between the shape of an enzyme and the reactions they catalyze?

2. how does an enzyme inhibitor work?

separate your answers so i dont get confused : )