Two species of tree frogs occupy different elevations in the canopy of a rain forest. If these frogs with strikingly different patterns of coloration but similar patterns of activity are brought together, they can produce offspring that survive to adulthood and can then mate successfully with individuals of either species. What keeps these frogs recognizably distinct?
1. Lack of hybrid fertility
2. Temporal isolation
3. Mechanical isolation
4. Habitat Isolation
5. Lack of hybrid viability

4. Habitat Isolation

Explanation:

Habitat isolation is a type of prezygotic reproductive barrier or isolation that occurs when two similar populations that can interbreed successfully are prevented from mating with each other as a result of being isolated by habitat. That is, they occupy different habitats. This is what keeps these frogs recognizably distinct.

tsd is temerature dependent sex determination.

tsd: it is a type of environmental sex determination in which the temperature experienced during embryonic/ larval development (ambient temperature for development) determine the sex of the offspring.

crocodile displays the tsd where the ambient temperature of the developing egg determines the individual's sex. for example in the american alligator's eggs, incubation at 33 ºc produces mostly males, while incubation at 30 ºc produces mostly females. so if the american alligator's egg will get the ambient temperature (33 degree celcius)during embryonic development from egg, the offspring will be male and same for the female sex determination.