Émuito comum ouvirmos dizer que o orvalho caiu. voce acha que essa expressão corresponde ao que de fato ocorreu?

When the word Storms is used in relation to climatic controls, we are not talking about tornadoes, hurricanes and the like. Rather this control deals with the presence of moisture in the atmosphere, the various means by which moisture is removed from the atmosphere and the forms the moisture takes. Meteorologists are very interested in the amount of moisture in the air not only because the presence of water vapor is an indicator of the potential for precipitation, but the energy released as water vapor changes states provides the energy for storms.
 Moisture, or humidity, is a general term we will use to describe the amount of water vapor in the air. There are a number of ways to express the amount of humidity in the air -- the most common being absolute humidity, relative humidity and mixing ratio. We will take up each of these shortly.

They create genetic variations