Final answer:
Thomas Hunt Morgan used fruit flies for genetic research because of their short life cycle and their simple chromosome structure, which facilitated the study of inheritance across generations and the identification of chromosomes' role in heredity.
Step-by-step explanation:
Thomas Hunt Morgan utilized fruit flies (Drosophila melanogaster) for his groundbreaking genetic research for two primary reasons. Firstly, fruit flies have a short life cycle, which allows for the observation of multiple generations within a short span of time, thereby making it possible to study the effects of genetic changes over those generations. Secondly, fruit flies have a relatively simple chromosome structure, which made them ideal for Morgan’s microscopic observations and for correlating specific traits with particular chromosomes—paving the way for the experimental evidence that supported the Chromosomal Theory of Inheritance.
These aspects of fruit flies, coupled with the fact they are easy to breed and maintain in a laboratory setting, made them perfect candidates for genetic study and contributed significantly to Morgan's Nobel Prize-winning research.