The correct answers are:
1 . They hold soil in place
2 . They store floodwaters.
The roles of mangrove trees are protective. Their dense root systems trap sediments flowing down rivers and off the land which helps in stabilization of the coastline and prevention of erosion from waves and storms. Also, mangrove trees provide natural barriers protecting coastal communities from flooding and hurricanes.
5.They filter water and improve water quality
Mangroves filter water with their dense network of roots and trap sediments, heavy metals, and other pollutants.