The smallest set $A$ such that $A  \cup  \{1, 2\} = \{1, 2, 3, 5, 9\}$ is

In each of the following, determine whether the statement is true or false. If it is true, prove it. If it is false, give an example.

If $A \not\subset B$ and $B \not\subset C,$ then $A \not\subset C$

Given the sets $A=\{1,3,5\}, B=\{2,4,6\}$ and $C=\{0,2,4,6,8\},$ which of the following may be considered as universal set $(s)$ for all the three sets $A$, $B$ and $C$

$\{ 0,1,2,3,4,5,6\} $

In each of the following, determine whether the statement is true or false. If it is true, prove it. If it is false, give an example.

If $x \in A$ and $A \not\subset B$, then $x \in B$

List all the elements of the following sers :

$F = \{ x:x$ is a consonant in the Englishalphabet which precedes $k\} $

Which of the following are sets ? Justify your answer.

A collection of most dangerous animals of the world.