To what part of a plant does the stem deliver water and nutrients? A) roots
B) seeds
C) leaves
D) soil

The first is the word “theory”, which means something slightly different in everyday speech than it does in science.

The second contentious word is “evolution”, because some people argue that there is insufficient evidence to support the idea that species change over time. Proponents of the latter view rely on our dual uses of the word theory to confuse the issues.

Source: http://theconversation.com/explainer-theory-of-evolution-2276