What should come next in the following letter sequence?

A A B A B C A B C D A B C D E A B C D

In the following question, from the given alternative words, select the word which cannot be formed using the letters of the given word.
Biological

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.
BT, DR, FP, ?

In the following question, which one set of letters when sequentially placed at the gaps in the given letter series shall complete it?
l m _ o _ n m _ l _ n _ _ n m l

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.
KV, LU, MT, ?

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.
CEG, IKM, OQS, ?

In the following question, which one set of letters when sequentially placed at the gaps in the given letter series shall complete it?
a _ bc _ a _ bcdabc _ da _ cd _

A series is given, with one term missing. Choose the correct alternative from the given ones that will complete the series.

T Q N K H E B Y V S P ? ? ?

A series is given with one term missing. Select the correct alternative from the given ones that will complete the series.
AG, LR, WC, HN, ?