a. Solid to liquid - melting process
b. Liquid to gas - evaporation process
c. Gas to solid - deposition process
d. Solid to gas - sublimation process
e. Liquid to solid - solidification process
f. Gas to liquid - condensation process
Answer: Alpha radiation
Explanation: Alpha decay : When a larger radioactive nuclei decays into smaller nuclei by releasing alpha radiation, the mass number and atomic number is reduced by 4 and 2 units respectively.

Beta decay : When a larger radioactive nuclei decays into smaller nuclei by releasing beta radiation, the atomic number is increased by 1 unit.

Gamma decay : When a larger radioactive nuclei decays into smaller nuclei by releasing gamma radiation, the mass number remains same.

After 2 half-lives there will be 25% (1/4th) of the original isotope, and 75% (3/4 th) of the decay product
<h3>What is Half life period ?</h3>
A half life is a measurement of the slope of an exponential decay function.
It is also defined as, the time it takes to halve the concentration of something in a process.
Each half life you will have half of what you had at the beginning of a given half life.
Learn more about half life here ;
brainly.com/question/9654500
#SPJ1