Sexual differentiation in humans Sexual differentiation in humans Sexual differentiation in humans is the process of development of sex differences in humans. It is defined as the development of phenotypic structures consequent to the action of hormones produced following gonadal determination. Sexual differentiation includes development of different genitalia and the internal genital tracts, breasts, body hair, and plays a role in gender identification. The development of sexual differences begins with the XY sex-determination system that is present in humans, and complex mechanisms are responsible for the development of the phenotypic differences between male and female humans from an undifferentiated zygote. Females have two X
What Is History? 19th century, western historians held to an empirical, positivist worldview that revolved around a "cult of facts", viewing historical facts as information that simply had to be assembled to produce an objective picture of the past that was entirely accurate and independent of any human opinion. Carr argues that this view is inherently flawed, because historians selectively choose which "facts of the past" get to become "historical facts", or information that the historians have decided is important. As an example, he notes that millions of humans have crossed the Rubicon river in Northeastern Italy, but that historians have only chosen