How many meaningful English words can be made with the letters $ARTSE$ using each letter only once in each word?

Which of the following series observes the rule,"Skip in between adjacent letters,increasing one letter more each time to build a set of letters"?

How many three-letter meaningful words can be formed from the letters of the word $TEAR$ beginning with $A$ without repeating any letter within that word?

How many pairs of letters are there in the word $FOREIGN$,each of which has as many letters between them as there are between them in the English alphabet?

If it is possible to make only one meaningful word with the first,fifth,ninth and the tenth letters of the word $'AUTOMOBILE'$,which would be the second letter of the word from the right? If more than one such word can be formed,give $'Y'$ as the answer. If no such word can be formed,give $'Z'$ as your answer.

Each of the following questions is based on the following alphabet series.
$A, B, C, D, E, F, G, H, I, J, K, L, M$
$N, O, P, Q, R, S, T, U, V, W, X, Y, Z$
How many $A$'s are there in the following series which are immediately followed by $B$ as well as immediately preceded by $Z$?
$A, M, B, Z, A, N, A, A, B, Z, A, B, A, Z, B, A, P, Z, A, B, A, Z, A, B$