1. Why is past consideration not consideration?2. Why are disguised gift promise

1. Why is past consideration not consideration?2. Why are disguised gift promises involving nominalconsideration nonbinding?3. A contracts to sell B his house for $100000. Later the partiesmodify the contract by changing the price to $110000. All otherterms remain the same. Is there consideration for the secondagreement? If the answer is no consideration state two ways inwhich the parties can circumvent this problem.4. In general settlements of liquidated debts are not binding dueto the absence of consideration while settlements of unliquidateddebts are a binding accord and satisfaction. As a matter oftechnical consideration law what justifies this distinction?