The opening is called an estuary.
Itβs called an estuary.
I believe that is from BC Science 7 and the answer is a delta.
the nile delta is a fan-shaped mud deposit at the mouth of the nile river
A river. Or a photo, statue, painting, or coin, all of which have mouths, but do not speak.
It is called a delta.
cataract
delta
cataract
An opening through which air or water can flow is a mouth. This can refer to the mouth of a river or a person or animal's mouth.
Delta.
The mouth of its river is shaped like one.
It is called a Delta.