About what fraction of earth's freshwater is in the form of ice

The first law of thermodynamics states that heat added to a system is neither created nor destroyed but is as it changes into other forms of energy.

Ihave this 50 question test the layer of earth's atmosphere where atoms and molecules escape into space is referred to as the a) exosphere b) ionosphere. c) mesosphere d) thermosphere

What kind of waves require a medium to travel? question 6 options: light waves mechanical waves all waves need a medium to travel electromagnetic waves