Limestone.
It is a sedimentary rock composed of calcite and aragonite. It is used as a building material mainly because it is easily available and easy to work with.
Limestone is used in the manufacture of steel as it is the primary raw material that helps to remove impurities from the iron ore and produces waste matter that has low melting point and viscosity
They both act like filters. The coffee filter makes sure that coffee doesn't go in the drink and the kidney makes sure solids don't pass by.
The cell wall because of the fact it is present in the plant cell and not in the animal cell
Americium, the atomic number is 93
