Examine whether the following statements are true or false :

$\{ a,e\}  \subset \{ x:x$ is a vowelin the English alphabet $\} $

Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?

$\{1,2,5\}\subset A$

State which of the following sets are finite or infinite :

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

Examine whether the following statements are true or false :

$\{ 1,2,3\}  \subset \{ 1,3,5\} $

List all the elements of the following sers :

$B = \{ x:x$ is an integer $; - \frac{1}{2} < n < \frac{9}{2}\} $

How many elements has $P(A),$ if $A=\varnothing ?$