How AC is a vertical summation of AFC and AVC cuves and pls clearify the meaning of vertical summation

AC is the vertical sum of AFC and AVC.

?MC is the slope of either VC or TC curve at a given point.?

?AC/AVC is the slope of a line from origin to the corresponding point on the TC/TVC curve.?

?MC curve pass through the minimum of AVC and AC

The total or "market" demand curve for a public good is obtained by the vertical summation of individual demand curves, which is in direct contrast to the market demand curve for a private good obtained by the horizontal summation of individual demand curves. Because public goods are nonrival in consumption, total or "market" demand is obtained by summing the value that each consumer obtains from a given quantity. For private goods that are rival in consumption, market demand is obtained by summing the quantity each consumer is willing to by at a given price.