It Is a Model Organism Used to Study Various Cell

It is a model organism used to study various cell and developmental processes such as the growth of developing body parts in the right place and with the correct shape. It develops from a fertilized egg to an adult in a little over a week, and has been a favorite of geneticists for almost a century. Some of its cells have giant chromosomes whose banding patterns have been extremely helpful in classical genetic studies. Which of the following describes this organism?

A) It is a vertebrate.
B) Its genome is only 10 million nucleotide pairs long.
C) There are many more duplicate genes in this organism compared to humans.
D) Although useful for genetic studies, the molecular mechanisms governing its development are irrelevant to human development.
E) It normally only reproduces sexually.