All but one statement could describe a scientific theory. that is: a) newly discovered evidence may disprove a theory b) scientific theories are frequently overturned by new evidence c) descriptive accounts of how nature will behave under certain conditions d) new evidence changes one part of a theory, while leaving the big picture intact

D is the wrong answer. New information does often completely change the theory. Its hard to change something and leave the major theory intact.

so easy. just google the electromagnetic waves and it’ll pop up.

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form