$1.$ Since this chapter is primarily definitions that are significant to business contracts, please explain $($in as much detail as possible$),$ what is a contract and how are contracts interpreted in the eyes of the law?

$2.$ In your narrative, please be sure to include definitions and$/$or examples explaining the following:

A$.$ Elements required for a valid contract

B$.$ Unilateral$/$bilateral contracts

C$.$ Express and implied contracts

D$.$ Valid, void, voidable contracts, and Quasi contracts.