Answer to Question 1
Contract is an agreement between two persons that is enforceable by law. The object must be legal in contract.
Express contract: A contract in which the terms are explicitly stated, usually in writing but perhaps only verbally, and often in great detail. In interpreting such a contract, the judge and/ or the jury is asked only to determine what the explicit terms are and to interpret them according to their plain meaning.
Implied contract: A contractual relationship, the terms and conditions of which must be inferred from the contracting parties' behavior toward one another.
Answer to Question 2
Employment-at-will holds that an employee who has not been hired for an express period of a year can be fired from his/her job by employer at any time with or without any reason. Both the employer and the employee are free unilaterally to terminate their relationship any stage without any compulsion or force. However there are exceptions under the doctrine. The most commonly adopted exceptions under employment-at-will is Public Policy exception. If a statute creates a right or a duty for the employee, he or she may not be fired for exercising that legal right or fulfilling that legal duty.