The sky on Earth is blue because blue light is scattered through the atmosphere as the other colors of light pass through undisturbed. Which nebulae have something similar going on?

Yes

Explanation:

Reflection nebulae mostly appear to have a blue colour. This is because particles in the nebula scatter (or reflect) blue light more efficiently than they scatter red light. The same effect is responsible for our sky being blue, not red, during the daytime.

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.