Understanding drag

Figure 1: Drag graph

Parasite Drag: Sum of Form drag, Interference drag and skin friction drag.

Induced Drag: by product of airspeed.  caused due to downwash....in a cambered wing, on the upward side air is flowing faster than the lower side. Now this fast moving air above and slow moving air below, meet at the trailing edge and cause turbulence called vortices. These vortices is downwash and it causes opposite reaction in form of drag called induced drag. Refer figure 2 below (RW = relative wind).

At low airspeed to maintain lift, pilot needs to increase AOA (angle of attack), as a result on the upside the air flows even faster as its more curved and lower side it travels the same speed. This causes even more turbulence at the trailing edge. Hence at low speed induced drag is more.
However at high speed, AOA is less and hence turbulence at trailing edge is less causing less downwash and less induced drag. Refer figure 1 above. 

Figure 2: Credits - Civil Air Patrol