PLEASE HELP!!

Please does anyone know the answer to this

What is the percentage by mass of silicon (si) in iron aluminum silicate (fe3al2(sio4)3)?

What’s the scientific notation for the number 6,840,000,000

Scientists have developed an explanation of a phenomenon from several verified hypotheses. the explanation has been confirmed through numerous experimental tests.which option best describes this explanation? a. scientific lawb. research questionc. hypothesisd. scientific theory