https://www.internetgeography.net/wp-content/uploads/2024/01/Internet-Geography-Logo.png00Anthony Bennetthttps://www.internetgeography.net/wp-content/uploads/2024/01/Internet-Geography-Logo.pngAnthony Bennett2020-07-06 15:56:072020-07-06 15:56:07Why does the long profile of a river become concave in the middle course?