Make correct statements by filling in the symbols $\subset$ or $ \not\subset $ in the blank spaces:

$\{ x:x$ is an even natural mumber $\}  \ldots \{ x:x$ is an integer $\} $

Examine whether the following statements are true or false :

$\{ a,b\}  \not\subset \{ b,c,a\} $

Which of the following are sets ? Justify your answer.

A team of eleven best-cricket batsmen of the world.

Write the following sets in the set-builder form :

${\rm{\{ 5,25,125,625\} }}$

State which of the following sets are finite or infinite :

$\{ x:x \in N$ and $x$ is odd $\} $

Let $S=\{1,2,3,4\}$. The total number of unordered pairs of disjoint subsets of $S$ is equal to