Q. Assertion Washing with water does not remove grease stains.
Reason Water does not wet greasy dirt.

 103  207 Mechanical Properties of Fluids Report Error

Solution:

Washing with water does not remove grease stains. This is because water does not wet greasy dirt, i.e. there is very little area of contact between them.
Therefore, Assertion and Reason are correct and Reason is the correct explanation of Assertion.