$2$ Counting

$2\mathrm{.}1$ A palindrome is a string whose reversal is identical to the string. How many bit strings of length $n$ are palindromes?:

$2\mathrm{.}2$ How many different ways are there to seat four people around a circular table, where two seatings are considered the same when each person has the same left neighbor and the same right neighbor?

$2\mathrm{.}3$ How many bit strings of length $10$ either begin with three $0$ s or end with two $0$ s $($or both$)?$ please answer with explanations