Answer:
Liquidity is a measure of how easily an asset can be converted into cash.
In order of most liquid to least, the above are:
1. A $10 Bill
This is already cash so is already as liquid as it will every get.
2. The funds in a savings account.
This can simply be withdrawn from the bank which will then give the customer cash so it is very liquid.
3. A share in a publicly-traded company.
This share would have to be sold first before cash is realized. The share is to a publicly traded company however so this will not be too difficult so this asset is adequately liquid.
4. Your car.
This would need to be sold first and finding a buyer might not be too easy so it is the least liquid of the bunch.