The origin of reproductive organs

Early in human development, during the first trimester of gestation, a fetus may have XX or XY chromosomes that indicate its sex. Yet at this stage a mass of cells known as the bipotential gonad that ultimately develops into ...

Bone, not adrenaline, drives fight or flight response

When faced with a predator or sudden danger, the heart rate goes up, breathing becomes more rapid, and fuel in the form of glucose is pumped throughout the body to prepare an animal to fight or flee.

Domestication syndrome: White patches, baby faces and tameness

More than 140 years ago, Charles Darwin noticed something peculiar about domesticated mammals. Compared to their wild ancestors, domestic species are more tame, and they also tend to display a suite of other characteristic ...

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