Describe one similarity and one difference between m& ms and actual radioactive decay

Iknow the answer is a but i don't know why

Mrs. smith ordered a root beer float (vanilla ice cream + root beer). mrs. smith noticed that the three states of matter (solid, liquid, and gas) all existed simultaneously in her root beer float. a. identify each phase of matter in the root beer float. b. describe the particles of all three phases of matter in the root beer float. (how are the particles arranged and moving? ) c. identify one phase change you would see in a root beer float and described what causes this change.

What happened to the amount of carbon dioxide in the atmosphere from 2010–2017?