Assertion: Mosses are of great ecological importance.
Reason: Mosses prevent soil erosion by forming dense mat on the soil

Answer: BSolution: Mosses along with lichens are the first orgainsms to colonis rocks and hence, are of great ecological importance. They decompose recks making the substance suitable for the growth of higher plants. Since mosses form dense mats ont the soil, they reduce the impact of falling rain and prevent soil erosion.