Why did lincoln inform the confederacy that he would not be sending troops or weapons as food supplies were sent to fort sumter?

Lincoln wanted the Confederacy to understand this action was not meant to be an attack, but an attempt to peaceably land only provisions.

South Carolina militia had declared that any attempt to resupply Fort Sumter would be seen as an act of aggression.  

Knowing the fort was running out of supplies, Lincoln announced his plan to send three unarmed ships to relieve Fort Sumter rather than sending a military expedition to reinforce and resupply.

by improved communication.

the section of the chart that represents a point at which a bill needs approval from a majority of people in both chambers to advance is j, as this is the only section before the bill becomes law which has both rows (symbolizing the chambers) converging into one, meaning that the two parts of the congress have to approve of it before it can march on with the process.