(N/A) Heavy water $(D_2O)$ is injurious to human beings,plants,and animals because it slows down the rates of biochemical reactions occurring in them.
Thus,heavy water does not support life and is not suitable for drinking.
Heavy water $(D_2O)$ is an oxide of deuterium,an isotope of hydrogen. It is extensively used as a moderator in nuclear reactors and in exchange reactions for the study of reaction mechanisms.
It can be prepared by the exhaustive electrolysis of water or as a by-product in some fertilizer industries.
Chemical reactions of $D_2O$:
$CaC_2 + 2 D_2O \longrightarrow C_2D_2 + Ca(OD)_2$
$SO_3 + D_2O \longrightarrow D_2SO_4$
$Al_4C_3 + 12 D_2O \longrightarrow 3 CD_4 + 4 Al(OD)_3$