What animals are in caves? How does the water flow? What type of work is it? Where does the water go? What does a cave look like?

What food is underground? Is the water healthy? Can the water kill the fish? How do bats live in caves? Can you drink the water in caves?

How much water is in caves? Would the water be safe to swim in? Can the water freeze in winter? Can the water evaporate in summer?