A shell is considered as biotic (living) because it is a hard, rigid covering of many animals such as snail, sepia, pila, turtles, sea urchins. A shell is protective outer layer of these soft bodied animals.
A hypothesis can become A. a scientific theory if it is supported by repeated experimentation.
When prolonged and excessive rainfall the more water percolates and the water table (below the earth surface/soil) rises. The higher the water table the more the possibility increases for a spring to form in the sense that it would now be easier for the water to find a means of escaping the underground through perhaps a crack or a cave, etc.
Answer:
I think its organic material from plants and animals
Explanation
Edge 2020
