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 $\} $

Let $A$ and $B$ be two non-empty subsets of a set $X$ such that $A$ is not a subset of $B$, then

Which of the following are sets ? Justify your answer.

The collection of questions in this chapter.

Write down all the subsets of the following sets

$\emptyset $

Examine whether the following statements are true or false :

$\{ x:x$ is an even natural number less than $6\}  \subset \{ x:x$ is a natural mumber which divide $36\} $

Decide, among the following sets, which sets are subsets of one and another:

$A = \{ x:x \in R$ and $x$ satisfy ${x^2} - 8x + 12 = 0 \} ,$

$B=\{2,4,6\}, C=\{2,4,6,8 \ldots\}, D=\{6\}$