This must be a homework assignment, and Avvo is the wrong site for you.
PS - you need to re-read the chapter. Offer and acceptance are always required. There may be consideration or a substitute for consideration (various types of estoppel, not just promissory.)
The above is general legal and business analysis. It is not "legal advice" but analysis, and different lawyers may analyse this matter differently, especially if there are additional facts not reflected in the question. I am not your attorney until retained by a written retainer agreement signed by both of us. I am only licensed in California. See also avvo.com terms and conditions item 9, incorporated as if it was reprinted here.
There must be a meeting of the minds, (i.e. offer and acceptance )to form a contract that is to be executed in the future. The terms must be definate or it can be enforced.
In order for a contract to be enforcible,, there must be consideration, or a substitute for consider (promissory esstopple). You don't have to have a formal offer and acceptance to form a contract - but there always has to be consideration.