Definition of ribbon. 1  1a : a flat or tubular narrow closely woven fabric (as of silk or rayon) used for trimmings or knittingb : a narrow fabric used for tying packagesc : a piece of usually multicolored ribbon worn as a military decoration or in place of a medald : a strip of colored satin given for winning a place in a competition.
Photosynthesis is the process by which organisms that contain the pigment chlorophyll convert light energy into chemical energy which can be stored in the molecular bonds of organic molecules (e.g., sugars). Photosynthesis powers almost all trophic chains and food webs on the Earth.
In general, there are two types of bonds. Sigma-bonds and pi-bonds. The electrons in a sigma bonds are concentrated along the line directly connecting two atoms. The electrons in a pi bond follow arc shaped geometry (above and below) the two bonded atoms. Because of this shape, pi bonds are sometimes called banana bonds.