Which statement is an example of a scientific theory?
A.
All living organisms are composed of one or more cells, which came from pre-existing cells.
B.
Hummingbirds do not like the color white because they visit other colored flowers more often.
C.
The amount that caffeine affects a person's heart rate differs based on the person's age.
D.
The Earth is the third planet from the Sun and has one moon, which orbits the Earth.