Answer:
The answer to your question would be that the verbs that correctly complete the sentence are the following ones: Record and studies.
Explanation:
The subject of the first part of the sentence is plural (instruments), so the verb should also be plural (record). Then, in the second part of the sentence, the subject (the scientist) is singular, so the verb should also be singular (studies). Subject verb agreement means that the subject and the verb must agree in number for the sentence to be grammatically correct. Both need to be singular or both need to plural.
