Complex sentence: The North Atlantic right whales nearly became extinct in the twentieth century, with a population low of 450, and is considered functionally extinct by cetologists, and the baiji is also considered functionally extinct by the IUCN with the last sighting in 2004.
Split into simpler sentences: The North Atlantic right whales nearly became extinct in the twentieth century, with a population low of 450, and are considered functionally extinct by cetologists. The baiji is also considered functionally extinct by the IUCN with, the last sighting in 2004.