Cell transport is useful because it's, essentially, the movement of cells across the blood/veins. Active transport uses energy, while passive transport does not.
Answer:
b. Theories unify a broad range of observations and hypotheses.
Explanation:
In broad terms, theories are the set of principles that can or must be used to explain certain phenomena. It involves the involvement or inclusion of any set of principles to get to a conclusion.
Hypothesis, on the other hand, is just a term used for an assumption made. And this assumption may be made even before any observation has been done, a mere suggestion for how to proceed with things or an assumption about things.
Thus, scientific theories unify a broader range of observations that had been done, including any hypothesis. So, the <u>correct answer is option b</u>.
