Which is a diatomic molecule? (I also need explanation so that I can understand what I am doing for school please thank you very much)

A.) He

B.) O2

C.) NaCL

D.) CuF2

Any is very appreciated! (picture is provided below)not sure how to do this at all won't lie

Afrequency table of grades has five classes (a, b, c, d, f) with frequencies of 3, 13, 14, 5, and 3 respectively. using percentages, what are the relative frequencies of the five classes?

Sanjay solved the equation below. which property did he use to determine that 7x+42=42 is equivalent to 7(x+6)=42 7x+42=42 7x=0 x=0