Which sentence describes two atoms that form a covalent bond?

Iknow the answer is a but i don't know why

Which statement best describes the relationship between period and frequency of light waves? a) in wave b the period increases and the frequency decreases from wave a. b) in wave a the period increases and the frequency decreases from wave b. c) in wave b the period is shorter and the frequency is greater than in wave a. d) in wave a the period is shorter and the frequency is greater than in wave b.

Ineed this asap part i: scientific method what is the difference between science and pseudoscience? what is the scientific method?