Why agar plates kept inverted whenever possible?

Question

Why agar plates kept inverted whenever possible?

Answer 1

Because the accumulation (and then dripping) of water vapor on the covering of the plate can contaminate the agar and effect the pattern of growth of organism that you are trying to grow.

Answer 2

To keep the condensation from dripping onto the agar.

Answer 3

This prevent condensation from getting onto the agar.  This would spread the bacteria around and make it impossible to pick out clones.