Question

brians aunt has cats. when brian recently visited her, he started sneezing badly and believes that it was because he is allergic to cats. what would be the next step for brian to form a hypothesis? by avoiding going to his aunts house by wearing a nose mask near cats by visiting other households with cats by visiting his aunts house again with the cats outside

Explanation:

To form a hypothesis about being allergic to cats, Brian needs to test the relationship between exposure to cats and his sneezing. Avoiding his aunt's house (first option) doesn't test the hypothesis. Wearing a nose - mask (second option) changes the variable (it's about the mask's effect, not just cat exposure). Visiting other households with cats (third option) has too many uncontrolled variables (different environments). Visiting his aunt's house again with cats outside (fourth option) isolates the variable of cat presence (he can check if sneezing occurs when cats are not around, which helps in forming a hypothesis like “If cats are removed from the environment, then I will not sneeze”).

Answer:

by visiting his aunt's house again with the cats outside