Answer:
Grant realized his access to men and supplies was almost unlimited, while Lee was running out of both.
Step-by-step explanation:
Before initiating the attack, The Union implemented a plan to cut off all of the distribution routes that can be used by the southern states to distribute their supplies.
This gave Grant a huge advantage over lee's forces during the siege in Northern Virginia.
The defensive line that Lee's created was difficult to break into. But, Grant he can win simply by surrounding the enemy. Eventually, Lee's forces will run out of food that they have no choice but to surrender.