Echidnas are marsupial mammals that have quills all over their body and look like placental hedgehogs. The two are not closely related. Echidnas are found in Australia and hedgehogs are found in Europe, Asia and Africa. Their resemblance is a result of which of the following? a. Adaptive radiation
b. Convergent evolution
c. Disruptive selection
d. Homologous features
e. Sympatric speciation