31.   Subspecies can usually interbreed to produce viable offspring.

32.   That genetic information came from a prize cow that had produced many offspring with excellent breeding characteristics but was too old to reproduce.

33.   That is, if two populations of a species live near each other, they will eventually mingle and produce offspring.

34.   The goal is to solve the mating puzzle so that pandas, a critically endangered species, will one day produce healthy offspring routinely.

35.   The men decided to breed sterile male screwworm flies and release them in the hope that they would mate frequently but produce no offspring.

36.   The most commonly used method has involved crossing two parents with different desirable characteristics in an effort to produce offspring that express the best of both of them.

37.   The pair produced five offspring but none lived more than five days.

38.   The oldest male, Toto, was not vasectomized because he never produced offspring and showed no interest.

39.   The odds are that most attractive members have what it takes to produce offspring best able to survive.

40.   The same mare mule foaled a female fathered by a jackass, but this female never produced any offspring.