On a cool morning, Uyen’s breath can form a cloud when she breathes out. Which changes of state are most responsible for Uyen seeing her breath in this way?

melting
condensation
deposition
sublimation

2. Vaporization and condensation.

Explanation:

First, it is important to know the definition of "Vaporization" and the definiition of "Condensation":

a. Vaporization is defined as the process in which the matter changes from liquid phase to gas phase.

b. Condensation is defined as  the process in which the matter changes from from gas phase to liquid phase.

Keeping the above on mind:

When we exhale, our breath contains moisture that comes from our lugs and mouth.

In we go outside in a cool morning, there our breath is in contact with the cool air.

When the above happens, the water vapor we breath out loses the energy it needs to keep in the form of water vapor.  Therefore, the water vapor begins to condense and it turn into  tiny droplets of liquid water and ice, which form the cloud mentioned in the exercise.