Select the most appropriate word to fill in the blank.
Loud fireworks also have an _____________ on glaciers.

The correct option is (a) effect.
Explanation: The word "effect" is a noun, meaning the result of a particular action. In this sentence, the word "effect" correctly describes the impact that fireworks have on glaciers. "Affect" is a verb and would not fit in this noun slot.
Meanings of all options:
· Effect: A change that is a result of an action.
· Affects: Verb form, meaning to make an impact.
· Effecting: Present participle form, which does not fit here.
· Affect: Verb, meaning to have an influence on something.
Correct sentence: "Loud fireworks also have an effect on glaciers."