Verbal Reasoning - Mental Ability Questions

Find the odd word/letters/number from the given alternatives.

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

Select the missing number from the given alternatives.

Select the missing number from the given alternatives?

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

NO, QR, UV, ZA, ?

In a certain code language, '+' represents 'x', '-' represents '+', 'x' represents '÷' and '÷' represents '-'. What is the answer to the following question?
642 x 6 ÷ 25 + 4 = ?

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

RS, WX, BC, ?

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

2, 7, 14, 23, 34, ?