Which of the following is the best evolutionary explanation

Which of the following is the best evolutionary explanation for the presence of flagellated cells in the life cycles of chytrids and their absence from other fungi? A. Chytrids are specialized fungi that evolved this trait from fungal ancestors that lacked flagellated cells. B. Presence of flagellated cells in chytrids shows that they are more closely related to animals and choanoflagellates than to actual fungi. C. Chytrids retain flagellated cells as an adaptation to living in water. D. Flagella have evolved repeatedly in many different eukaryotic groups, and their presence is evolutionary meaningless. E. Flagellated cells in chytrids are a remnant of the common ancestry of fungi, animals, and choanoflagellates that has been lost in other fungi.

Solution

C. Chytrids retain flagellated cells as an adaptation to living in water.

During the course of evolution Chytrids are not found to be the oldest fungi because presence of fungi fossils, older than Chytrids have also been reported but Chytrids do give a picture of ancesstors of fungi.

Chytrids were predominantly aquatic habitants, so their gametes possessed flagella, for convinient swimming in water. This also tells about evolution that fungi started in auatic habitats. Flagella must have been lost in other fungi when evolution progressed from aqautic to terrestrial habitats.