After sitting quietly for 500 years, mount pinatubo began erupting. first, it oozes lava, when it hurled ash and cinders high into the atmosphere. this is an example of..

A non explosive eruption followed by an explosive eruption.

Explanation:

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.