Question

Volume is an unreliable measurement because 

Answer 1

D cause gas is an air unless you mean car gas then anyways its D

Answer 2

Answer with explanation:

Why volume is an Unreliable Measurement, This can be explained by taking example of Compound water.

There are three states of water

1. Solid state , which is when temperature goes below 0° C

2. Liquid State,when temperature goes above 0° C

3. Gaseous state, when temperature goes above 100°C.

When you measure , water in three different States in any container ,their mass or volume's are different.That's one of the reason Volume is considered to be unreliable measurement .

Option D:  gas weighs less than liquid.