Question

1. a group of kids are making fun of the new student. i should step in and stop them.
2. the chemical formula for water is h₂o.
3. red is my favorite color.
4. it is better to be a democrat than a republican.

Explanation:

1. The statement "I should step in and stop them" is a personal - value based judgment, thus an opinion.
2. The chemical formula for water ($H_2O$) is a fact verified by scientific research and experimentation.
3. Stating a favorite color is a personal preference, so it is an opinion.
4. The statement "It is better to be a Democrat than a Republican" is an opinion as it reflects a subjective political preference.

Answer:

1. Opinion. Reason: It shows a personal belief about what one should do.
2. Fact. Reason: Scientifically verified chemical formula.
3. Opinion. Reason: Describes a personal preference.
4. Opinion. Reason: Reflects a subjective political preference.