Which of the following will only affect the reaction rate of gases? A. Concentration
B. Catalyst
C. Pressure
D. Surface area

D. Pressure

Explanation:

The rate of a reaction is defined as the speed at which the reactants are converted into products. Factors influencing the rate of a reaction are concentration, catalyst, temperature, surface area,  and pressure, etc.

In case of the reaction rate of gases, pressure will only have its affect as pressure do not have any influence on solid and liquid.

While concentration, surface area and catalyst influence all reaction rates including solid, liquids and gases.

Hence, the correct option is (d) pressure.

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.