Question

What cross leads to the production of the mule?

Answer 1

Part 1: Introduction of interspecific hybridisation
Interspecific hybridisation is a method of breeding, in animals. It is a process of mating between animals of different species.

Part 2: Production of mule
Mule is produced by interspecific hybridisation between male donkey and a female horse.
When two different species which has different chromosome numbers are crossed, it results in an offspring which is infertile. Hence mules are infertile.