Ubwonko ni igice cy’urwungano rw’imyakura rworohereye cyane, rwangirika ubusa, kandi rushobora kwangizwa na byinshi. Ubwonko kandi ni rwo rugingo rusobetse cyane, ndetse ruruhije gusobanukirwa mu mikorere yarwo kuko bugizwe n’ingirangingo fatizo zigera kuri miliyari ijana(100.000.000.000). Kuva mu isamwa kugera…