Which Examples Would Be Considered Different Species Under the Biological

Multiple Choice

Which examples would be considered different species under the biological species concept? Check all that apply.

A) Two bear species are able to breed in zoos,but have separate ranges in nature.
B) Two skunk species look morphologically similar,but are unable to interbreed.
C) Two snake species look different,but often form fertile hybrids.
D) Two plant species with no gene flow between them.
E) Two tree species have different leaf shapes,but form hybrids in their overlapping ranges.