I can’t get spoiler tag to work so here it is
The seeds at least need to contain cells, because new plants with cells grow out of them. It’s not a single cell because it’s solid on the inside—I don’t know any living cell that is, and it would be very difficult for substance transport. It also shows cell damage: a cut apple browns on the air, and the sharper the knife the less it does it. I don’t think a case like bones can even be excluded without a microscope.
How normal would you rate the reaction? While you were being rude, I find it strange to complain to the teachers about just that. In my experience, not many people would do that past elementary school.