B is the correct answer.
The exosphere is the outermost region of the atmosphere the gradually merges out into space. The water cycle does not occur within this region.
The rover was designed to explore A.Mars
Answer: the answer is B!
Explanation:
S and p’s are valence electrons and if added, there is 7 in total !
Helium,it has an atomic mass of 4,which means total no. of protons and neutrons,so I think you meant 2 protons and an atomic mass of 4
