How does understanding radioactive decay scientists?

Radioactive decay involves the unplanned transformation of one element into another. The only way that this can happen is by changing the number of protons in the nucleus (an element is described by its number of protons). There are a number of ways that this can happen and when it does, the atom is forever changed. There is no going back -- the process is irreversible.

a  solution  is always transparent, light passes through with no scattering from solute particles which are molecule in size. the  solution  is homogeneous and does not settle out. a colloid is intermediate between asolution  and a  suspension. while asuspension  will separate out a colloid will not.

im not exactly sure but i think its b!