I believe the term for an observable trait of an organism would be called or noted as the organism's phenotype.
<span>maintains a constant INTERNAL environment
so other options included internal variable and external environment. but its internal and environment</span>
Answer:
This can be caused by mating differences, sterility or environmental barriers that eventually lead to the adaptive splitting into two species. ... However, reproductive isolation is not sufficient but internal barriers to gene flow are required for speciation to evolve.
Explanation:
I hope this helps I'm not so good at explaining.
