The appendix in humans is a vestigial organ. in other mammals, it is not vestigial and is larger because it to digest a certain type of plant material. which statement most likely describes the appendix’s lack of function in humans? a-the diet of humans no longer includes as much plant material. b-the diet of humans is the same as other mammals. c- the human digestive system is less effective compared to other mammals. d-the human digestive system relies heavily on the appendix.