What is the observation made about the presence of flies and maggots in the jar with and without a cover?
1) Flies and maggots are found in the jar with no cover but not in the covered jar
2) Flies and maggots are found in the covered jar but not in the jar with no cover
3) Flies and maggots are found in both the jar with no cover and the covered jar
4) Flies and maggots are not found in both the jar with no cover and the covered jar