help me answer this

1. x was in desperate need of money, so he sold the car of his father, y, to z. Upon learning of the sale y called Chito and asked him how much x sold the car to him and after that did not contact z further. Was the sale between x and z valid? Explain

2. A owns a wholesale grocery store and ordered from xyz Food Co. a large 100 kilo sack of puppy food. Upon delivery it was discovered by A that what was delivered was a mix of adult dog food and puppy food due to the slight difference and shape and color. What can A do regarding the sale? Explain

3. X sold Z his car. They agreed that Z can pay X whatever amaount he likes as long as he tells him how much first before he pays. Is there a valid contract of sale between X and Z? Explain

4. X bought the Horse of Y through a verbal agreement. Is the sale valid? If valid Why? If invalid why not?

5 X stored 1 kilogram of Gold worth P3,000,000.00 in the warehouse of Y. Y issued a warehouse receipt which is deliverable to bearer. Z, to whom Judy P2,000,000, learned of the gold stored in the warehouse of and now seeks to levy the gold in order that the debt would be paid. X had already negotiated the warehouse receipt to W and further negotiated the wareahouse receipt to S by delivery but insists that it there must also be indorsement. Can Z still have the gold levied or garnished? Can S insist that there should be an indorsement of the warehosue receipt?