Which statement correctly describes why a compound is a pure substance?

If we compare and contrast electromagnetic waves with sound waves, all but one statement is true. that is a) sound waves require a medium to travel while electromagnetic waves do not. b) electromagnetic waves can travel through the vacuum of space while sound waves cannot. c) electromagnetic waves must have a medium in which to travel, but sound waves can travel anywhere. eliminate d) sound waves must bounce off of matter in order to travel while electromagnetic waves do not require matter to be present.

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

Which fossil fuel is mainly used for heating and cooking? a. electricity b. coal c. petroleum d. natural gas