Cube a has a volume of 2cm x 2cm x 2cm. what is its density

The volume of the cube is (2cm x 2cm x 2cm) = 8 cm³ .

The density of the cube is

       (the mass of the cube, in grams) / (8 cm³)        grams per cm³ .

That's the best I can do, because you haven't told us the cube's mass.
 

Protons have a positive charge and, collectively, give an element its atomic number.

Honestly "global warming" may be a slight possiblity, however they called it "climate change" because its not real, in fact we had one of our coldest days here not too long ago, and the "issues" with this subject is a blindfold for actual problems.