Help the sociology student polish her methodology section by choosing the correct article for each blank. (Use '--' to indicate that no article is needed).

In -- qualitative research, the mere presence of an observer can inadvertently trigger an artificial response from the participants.

In -- qualitative research, the mere presence of an observer can inadvertently trigger an artificial response from the participants.

-- : "Qualitative research" is an uncountable abstract noun used here in a broad, general sense, so it takes the zero article.

the : "Mere presence" requires the definite article because it is made highly specific by the post-modifying prepositional phrase "of an observer."

an : "Artificial response" is a singular countable noun being introduced for the first time. Because there are many possible types of responses, it takes the indefinite article "an" (matching the vowel sound of "artificial").