Morgan chose fruit flies (Drosophila melanogaster) as the study model for his experiment. Certain reasons made this organism suitable for the study. Which of the following is not one such reason?

• A

  They could be grown on simple synthetic medium in the laboratory.

• B

  They take about 6 weeks to complete their life cycle.

• C

  A single mating could produce a large number of progeny flies.

• D

  The male and female flies are easily distinguishable.