What is the correct order of the stages of speciation? it a)1. the populations are isolated and those do not interbreed 2. the population become adapted to different environments and eventually become so different that they cannot interbreed to produce fertile offspring 3. the populations become totally separated from one another b) 1. the populations become totally separated from one another. 2. the populations are isolated and thus do not interbreed. 3. the populations become adapted to different environments and eventually become so different that they cannot interbreed to produce fertile offspring. c) 1. the populations are isolated and thus do not interbreed. 2. the populations become totally separated from one another. 3. the populations become adapted to different environments and eventually become so different that they cannot interbreed to produce fertile offspring