When frost forms:

(A) when an outside surface cools past the dew point
(B) water vapours change into ice without becoming liquid
(C) below the dew point
(D) All of above

Answer: (A) when an outside surface cools past the dew point

The most necessary property of a reservoir is:

(A) Porosity
(B) Permeability
(C) Voids
(D) None of these

Answer: (A) Porosity
The most necessary property of a reservoir is porosity and permeability, but between porosity and permeability, the most necessary property of a reservoir is porosity.