Ablank may form where a river enters a large body of water, such as a lake or an ocean. what is the "blank"?

i think

1. continental slope

2. continental rise

3. continental shelf

mark me branliest, only got it 1 time

primary succession occurs in essentially lifeless areas regions in which the soil is incapable of sustaining life as a result of such factors as lava flows, newly formed sand dunes, or rocks left from a retreating glacier. secondary succession occurs

answer diabetes mellitus;