Identifying the odd one from the following. 

  

If cos-1 (1/√5) = θ then what is the value of cosec-1 (√5) ?

If log2 (log3 (log2 x)) = 1, then what is the value of x ?

The roots of the quadratic equations      1/(a + b + x) = 1/a + 1/b + 1/x, a + b ≠ 0

The digit in the unit place of (2018)2018 + (2019)2019 + (2020)2020 is :

How much energy the producer trophic level will have if the amount of energy available at the third trophic level is 10 J ?

Mucor and Aspergillus are examples of :

Identifying the odd one from the following. 

After ovulation graafian follicles regress into :

Which one is used in energy generating nuclear reactors ?

which state of India has the largest forest area ?