In what ways do both U.S. law and the CISG contemplate circumstances beyond a party’s control?

In what ways do both U.S. law and the CISG contemplate circumstances beyond a party’s control? How are these similar and different from each other?

There are three main differences between the Uniform Commercial Code UCC and Contracts for the International Sale of Goods CISG. First, in the UCC goods of $500 or more are not enforced unless it is indicated in writing that both parties have a contract, and it should be enforced on one of them. The CISG says there is no need for a written contract and can be proved by anything, even witnesses. Second, UCC terms of agreement can’t be contradicted by evidence of previous agreements. CISG lets parties negotiate and see how parties interpret their contract. Third, CISG says that if there is an offer that has more terms, it means the previous offer is not valid and this is considered a counter offer. UCC says that even if the terms have additions or differ from the offer, by accepting, it is considered effective.

Similarity is that UCC and CISG allow the seller to cure a shipment if it is done within the time stated in the contract. In both of them the buyer can take back the acceptance if the good is defective, return it and get the money back. Also, if there is no timely notice, the buyer can’t say that the seller breached the contract.