Sec 3(1) of cap 31(sale of goods act) has defined a contract of sales of goodsas on which the seller transfers or seller agrees to transfer properly

Sec 3(1) of cap 31(sale of goods act) has defined a contract of sales of goodsas on which the seller transfers or seller agrees to transfer properly in goods (ownership) to the buyer in exchange of money consideration called the price.

Briefly explain the difference between two different situations which are envisaged by the definition.