Hydrophobic molecules dissolve in water due to their polarity.

A jumbled word is given here. Write the correct form of the word.
WASHFERRET

Why should water be treated to make it potable for human use? 

Match the following:

Represent the union of two sets by Venn diagram for each of the following.

$X=\{x | x$ is a prime number between $80$ and $100\}$

$Y=\{y | y$ is an odd number between $90$ and $100\}$

Complete the flow chart