Let $a, b, c$ be real numbers. $A$ set formed with $a, b, c$ whose order of occurrence is preassigned is called:

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

Let $A = \{1, 2, 3, 4, 5, 6\}$. Insert the appropriate symbol $\in$ or $\notin$ in the blank space:
$4 \dots A$

If $A = \{1, 2, 3, 4, 5, 6\}$, then which of the following is not true (in $in A$)?

The set $\{n(n+1)(2n+1) : n \in \mathbb{Z}\}$ is a subset of:

In a city,no two persons have an identical set of teeth,and there is no person without a tooth. Also,no person has more than $32$ teeth. If we disregard the shape and size of the teeth and consider only the presence or absence of a tooth at each of the $32$ positions,then the maximum population of the city is: