(a) A banana bond is also known as a bent bond. It is a type of chemical bonding where the ordinary hybridization state of two atoms making up a chemical bond are modified with increased or decreased s-orbital character in order to accommodate a particular molecular geometry (that of 3 bananas in a ring shape).
(b) Boric acid is low in toxicity if eaten or if it contacts skin. However, in the form of borax, it can be corrosive to the eye. Borax can also be irritating to the skin. People who have eaten boric acid have had nausea, vomiting, stomach aches, and diarrhea.