Sand dollars are radially symmetrical and have an internal skeleton but no backbone. Which phylum do sand dollars belong in? chordates
echinoderms
arthropods
mollusks

echinoderms

Explanation:

they are in the same family as starfish and sea urchins

thymine. in rna, thymine is replace by uracil

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.