Misc: dr. ---------- coined the word nerd in his 1950 book 'if i ran the zoo.'?

Questions

the violet belongs to which genus of flowers?

on the body what is a calcaneium?

what is the name given to the young of 'dragonflies' and 'damselflies'?

in 1846 american inventor elias howe patented what type of machine?

sea cucumbers are a type of what?