Question

River creates _______ at their mouths.

Lagoons
Estuaries​

Answer 1

Answer:

estuaries

Explanation:

the mouth of a river is the region when it finally flows into a larger waterbody, and this larger waterbody usually being of a saline source like oceans, the rivers create estuaries

estuaries are formed when fresh and saline waters meet like rivers and oceans

lagoons are pond like things which are separated from the main water body