There are three main types of plate boundary: divergent, convergent and transform. Plates move away from one another at divergent boundaries. This happens at mid-ocean ridges. Plates move towards one another at convergent boundaries; one plate is forced below another in a process called subduction.
The skin of a Concord grape is typically dark blue or purple, and often is covered with a lighter-coloured epicuticular wax bloom that can be rubbed off. It is a slip-skin variety, meaning that the skin is easily separated from the fruit. Concord grapes have large seeds and are highly aromatic.
Concord and zinfandel are some of flavorful blue-black cultivars. Commercially, many cultivars of grapes are grown for different purposes either to be eaten as table fruit, fresh or dried (raisin, currant, sultana) or in wine production. Grapes are rich in polyphenolic phytochemical compound resveratrol. Resveratrol is one of the powerful anti-oxidant which has been found to play a protective role against cancers of colon and prostate, coronary heart disease (CHD), degenerative nerve disease, Alzheimer's disease and viral/ fungal infections.