Here is the list of pronouns in the order they appear in the text, assigned to their particular groups:
1. interrogative pronouns (the ones who ask a certain question): WHAT, WHAT
2. possessive pronouns (the ones which show a certain possession): YOURS, YOURS
3. personal pronouns (I, you, he, she...): IT, IT, YOU, YOU, YOU, IT, US
4. indefinite pronoun (you cannot exactly determine who it is about): EVERYONE, ANYONE, SOME, ALL, EACH
5. relative pronouns (connect a clause to a noun/pronoun): WHO, THAT, WHATEVER
6. demonstrative pronouns (point to a particular thing): THESE
A calorie is a unit that is used to measure energy.
Answer:
The first firefighters to arrive on the scene had only limited waterpower
Researchers are someone who searches about someone and learns about someone's daily lives or talents.
