Category: one liners: knock knock/who's there/oj/oj who??

Questions

Material withheld from civilian use in WW II because it was needed to make parachutes?

Mature ovary in flowering plants, together with all inseparably connected parts of the flower?

Maxillary palps, abdomen, & metathorax are parts of a(n) ________?

Medical examination of a dead human body, including the internal organs, to determine the cause of death or to study pathological changes?

Members of the nazi ss had their blood type tattooed where?