Directions: Which of the phrases given below the sentence should replace the underlined phrase to make the sentence grammatically correct? If the sentence is correct as it is, select "No improvement required".

Because the transferred researcher was unable to collaborate by another scientists, she requested a separate laboratory space.

The correct answer is collaborate with other scientists, she.

Step-by-step explanation:

1. Correct Preposition: The verb collaborate requires the preposition with when referring to working jointly with people. The phrase "collaborate by" is grammatically incorrect.
2. Determiner Choice: The word "another" is used with singular countable nouns (e.g., "another scientist"). Since "scientists" is a plural noun, it must be preceded by other to form "other scientists".
3. Verb Form and Subject-Pronoun Agreement: The phrase "unable to" is followed by the base form of the verb (infinitive collaborate). Additionally, the pronoun she correctly agrees with the singular subject "the transferred researcher".

Replacing the underlined phrase yields the grammatically correct sentence:
"Because the transferred researcher was unable to collaborate with other scientists, she requested a separate laboratory space."