https://gradetutors.com/wp-content/uploads/2019/09/logo2.png00adminhttps://gradetutors.com/wp-content/uploads/2019/09/logo2.pngadmin2020-06-21 21:20:022020-06-21 21:20:02if the concept is truck, the prototype might be? if the prototype is block or ball, the concept is?