How many constitution isomers does C5H10 has? Saturated molecule?

The 6 acyclic isomers (i.e. without ring structure) of C₅H₁₀, including structural isomers and geometrical isomers, are shown below. All of such isomers are unsaturated because they all have C=C double bonds.

This is a badly worded question:
I think that the asker wants to ask:
What are ther saturated isomers of C5H10
There are in reality 3 saturated isomers:
The isomers are:
Cyclopentane
Methylcyclobutane
1,2-dimethylcyclopropane .

C5H12 (Saturated) has just three. Saturated C5H10 is cyclopentane and its isomers. There are three structural isomers, two enantiomers and a diastereomer.