What percent of immature T cell thymocytes are eliminated and destroyed by thymic selection to prevent autoimmune diseases?

These cells continue to mature and then exit the thymus, armed to inhibit the activation of self-reactive T cells. It has been estimated that the three steps of thymic selection eliminate 98% of thymocytes.

answer: tributaries flow into rivers.

wetland is a biome that develops when the water gets accumulated in a land exhibiting a huge depression. these form either seasonally or permanently. the water in the wetland comes from rivers, lakes, ocean, flood, rain or other sources. the wetlands includes mangroves, marshes and peatland.

tributaries flow into the rivers develops a wetland because such water will get deposited in the depression and will restrict the original flow of tributary water. hence, water with low drainage current combines with the river water.