Question

A mule is an example of _________. select one:
a. hybrid inviability
b. hybrid breakdown
c. none of the alternatives provided are correct
d. a postzygotic barrier

Answer 1

A mule is a hybrid between a horse and a donkey (a male horse and a female donkey). Mules cannot produce offspring so it is under Hybrid Sterility, which falls under Letter D: a postzygotic barrier.
A postzygotic barrier diminishes the ability to reproduce of hybrid offsprings.

Answer 2

The correct answer is D.