Final answer:
Sex determination in diapsids, including reptiles, is influenced by sex chromosomes and environmental factors such as temperature, with the latter known as temperature-dependent sex determination. Although sex chromosomes play a role, the temperature during egg incubation significantly affects the sex of the offspring, with variations in whether cooler or warmer temperatures produce males or females.
Step-by-step explanation:
The sex determination mechanism varies across different species. In diapsids, which include reptiles such as alligators, some turtles, and tuataras, sex determination is not only dictated by the presence of sex chromosomes but also can be influenced by environmental factors. Specifically, the temperature during the middle third of egg development can play a crucial role, a process known as temperature-dependent sex determination.
In many turtle species, lower incubation temperatures tend to produce males, while higher temperatures may yield females; however, this can vary by species. Meanwhile, in some crocodilian and turtle species, intermediate temperatures result in male offspring. It's worth noting that the statement about mammals having XX (homozygous) males and XY (heterozygous) females is incorrect; in mammals, females are typically XX and males are XY.