Final answer:
The processes that lead to the formation of the letter A are sublimation and deposition, which involve the transition between the solid and gas phases without passing through the liquid phase. Sublimation requires energy input, whereas deposition releases energy.
Step-by-step explanation:
Sublimation is a process where a solid transitions directly to a gas without passing through the liquid phase. An example of this would be dry ice turning into carbon dioxide gas. On the other hand, deposition is the reverse process, where a gas transitions directly into a solid, such as frost forming on a cold surface from water vapor in the air.
The process of sublimation requires an input of energy to change a solid into a gas, combining the necessary heat of fusion and heat of vaporization. In contrast, during deposition, which is the opposite of sublimation, energy is released as gas molecules form intermolecular forces while transitioning to the solid phase.
Processes like evaporation and condensation are also involved in phase changes of matter but pertain to transitions between liquid and gas, not affecting solid directly transitioning to gas or vice versa. Therefore, choices B) Melting and freezing, C) Evaporation and condensation, and D) Precipitation and dissolution are not correct in this context.