Mammals, like humans and apes, have 5 digits on their fore and hind limbs. Modern horses have 1. How might you recontrust the ancestral state of mammal tow number?
a) investigate the number of toes on all extant horses and apes
b) investigate the number of toes for other mammals and use parsimony to deduce the ancestral state
c) investigate the number of toes for an outgroup that is closely related to mammals, for example reptiles or amphibians
d) either b or c
e) all of the above