please let me know if the answer is true or false. if false, please tell me what's false about it. the word that they are wondering if it needs to be changed is highlighted​

Calculate the molar mass of aluminum oxide (al2o3). express your answer to four significant figures.

What layer of the atmosphere is directly above the troposphere?

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.