Respuesta :
Answer:
1. Reciprocal pronoun. (one another)
2. Personal subjective pronoun. (they)
Explanation:
In the sentence "scientists test one another's hypotheses to make sure they are sound" we can identify two type of pronouns. The first one is called "reciprocal pronoun" and It is used when there is two, three or more people involved in the action. The second pronoun is called "personal subjective pronoun" because It is a personal pronoun used as the subject of the verb.