As a child, you may have dug in the dirt and played around with
Platyhelminthes: flatworms
Nematode: roundworms
Annelida: segmented worms
Mollusca: mollusks

Annelida : Segmented worms

Explanation:

because Earthworms come under this category and are the ones who most commonly occur in the dirt.

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.

b. lithosphere, asthenosphere, mesosphere   is the answer most likely