Choose the correct alternative for the missing terms in the series: $Y, W, U, S, Q, ?, ?$

Fill in the blank space for the given series with the correct alternative.
$9, 11, 20, 31, (...), 82$

The positions of the first and the fifth digits in the number $53216894$ are interchanged. Similarly,the positions of the second and the sixth digits are interchanged,and so on. Which of the following will be the second from the right end after the rearrangement?

Choose the correct alternative for the missing term in the series: $AYD, BVF, DRH, ?, KGL$

Find out the wrong term from the given series.
$445, 221, 109, 46, 25, 11, 4$

Choose the correct alternative to fill in the blanks in the series: $ab...bbc...c...ab...ab...b$