North Carolina Grade 8 End-of-Grade (EOG) Science Practice Test

Flu spreads mainly through close, person-to-person contact when someone who is sick talks, coughs, or sneezes, releasing respiratory droplets that others nearby can inhale. In a crowded event like a school dance, many people are in close proximity, making it easy for those droplets to reach multiple mouths or noses. That pattern fits the scenario of ten people becoming sick after attending the dance, because the illness is spreading directly from one infected person to others nearby.

Environmental sources and contaminated objects can play a role in some illnesses, but they’re less likely to explain a rapid outbreak among many people at a single event. A virus on a surface would require several steps (someone touching the surface, then touching their face) and often results in slower or more varied timing. Infected animals are not a typical source for a flu outbreak in a school setting, so that doesn’t fit this situation well.

So, the best explanation is that the illness spread through contact with an infected person, especially given the close, crowded conditions of the dance.