Verbal Reasoning - Mental Ability Questions

Which set of letters when sequentially placed at the gaps in the given letter series shall complete it?

MN_NOM_OPM_OP_

If A = 1, E = 5, then HEAR = ?

If MARBLES is coded as PDUEOHV, then how will GIN be coded as?

Select the related word/letters/number from the given alternatives.
Frog : Amphibian : : Cobra : ?

Select the related number from the given alternatives.
7.25 : 7.75 :: 9 : ?

A series is given, with one word missing. Choose the correct alternative from the given ones that will complete the series.
Oxygen, Toil, Arouse, Arson, Tenuous, ?

Select the odd word from the given alternatives.

In the following question, select the related word pair from the given alternatives.
Heart : Organ : : ? : ?