Jellyfish, corals, and hydras are examples of which of the following? tentacles phylogeny cnidarians sponges

Legumes, a type of plant, require rhizobia, a type of soil bacteria, to survive since these organisms fix nitrogen during photosynthesis. rhizobia use the legumes for food. what would most likely happen to the legume population if rhizobia suddenly became extinct?

The buildup of sediments where a river empties into a slow-moving or nonmoving body of water is known as a/an

Ialready know the answers to these questions and they are on the attachment. but i just need to know why that answer is the correct one. plz asap! this is for a report that i need to email by 10!