Explanation:

These three statements are the main features of zabti system.
There was no Mughal land revenue system before Akbar. His father Humayun and grandfather Babur did not introduce any changes because they were the first conquerors of their dynasty and remained pre-occupied with subduing rebellions, consolidating empires and maintaining order.
A proper land revenue system was founded by Akbar. However, the system of Akbar was itself based on what Shershah Suri implemented during his short tenure. Thus, the land revenue system of Akbar was neither an innovation nor an invention. His indebtedness to the earlier rulers is immense but this has not diminished his fame as far as land revenue system is concerned. He followed the policy of Shershah with greater precision and correctness and then extended it to various subahor provinces of his empire. But this correction or precision did not came overnight. Initially was tortuous enough to turn peasants into beggars, and forcing them to sell their wives and children. But it was revised several times.
The first question is – what were the corrections and precisions Akbar did in the existing system created by Shershah? The corrections done by Akbar in land revenue system can be mainly divided into three heads as follows:
•    Standardization of measurement of land
•    Ascertaining the produce per Bigha of Land
•    Fixation of state’s share in that produce