Despite there being no answers listed by you, which the problem seems to be a multiple choice type of question, I'll go ahead and take a stab here.
What this problem is describing is basic nuclear fusion. Nuclear fusion is the process of which energy is released by a combination of two elements after they form into a brand new element. Once this happens, the bonded atoms have formed into a new, heavier nucleus.
D.mesa mesa is table in spanish, technically mesa's arent supposed to have a slope.
We can use light absorption technique to determine which element this atom belongs to.
When light meets an atom it is absorbed. The particles of light (photons) are absorbed by electrons and electrons jump to a higher energy state. When electron jump to a lower energy state they emit photons. If we observe continuous spectrum of a light that comes from this atom we can see black stripes. These stripes are unique for each atom and represent these jumps that electron made. By comparing observed stripes with those that were found in a laboratory we can figure out which element this atom belongs to.
