It may be a lake, a marsh, a spring or a glacier. This is where the stream starts. The source is the farthest point of the river stream from its estuary or its confluence with another river or stream. ... The farthest stream is called the headstream or headwater.
The correct answer of the given question above would be option D. The option that did not occur during the Cenozoic era is the formation of the ozone layer. The ozone layer has long been there before any era since it is part of the earth's atmosphere. Hope this answer helps.
D should be the answer as they are no longer able to perform sexual reproduction without the other fish. Therefore, they would die off because they have lost the partner needed to reproduce.
Hope this helps!
