Question

read the paragraph, then choose the word that best completes the sentence. scientists have discovered that people carry a staggering variety of bacteria on their hands. they found a total 4,742 different species. individual test subjects averaged 150 different types, with women averaging more types of bacteria than men. scientists are not sure why but have offered several possible explanations. the differences may have something to do with acid on the skin. a mans skin generally has more acid than a womans skin does, and bacteria do not thrive as well in more acidic environments. another cause could be the differences in sweat and oil produced. makeup use could also make a difference, as could skin thickness. scientists have created many _______. a hypotheses b patents c routines d formulas

Explanation:

The text states that scientists are not sure why there are differences in the types of bacteria on men's and women's hands but have offered several possible explanations. A hypothesis is a proposed explanation made on the basis of limited evidence as a starting - point for further investigation. So "hypotheses" fits the context as the scientists' possible explanations are hypotheses. Patents are related to legal rights for inventions, routines are regular procedures, and formulas are mathematical or chemical expressions, none of which fit the context.

Answer:

A. hypotheses