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[16] [17] IQ tests that measure fluid g and have not been constructed to eliminate sex differences also tend to show that sex differences are either non-existent or negligible. [17] [18] 2008 research found that, for grades 2 to 11, there were no significant gender differences in math skills among the general population. [19]
Sexual differentiation includes development of different genitalia and the internal genital tracts and body hair plays a role in sex identification. [ 2 ] 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 ...
Mutation and selection. The concept of sexual selection was introduced by Charles Darwin as an element of his theory of natural selection, [1] Sexual selection is a biological way one sex chooses a mate for the best reproductive success.
The gender gap in life expectancy suggests differences in the aging process between males and females. A key factor underlying aging is considered to be DNA damage, particularly DNA double-strand breaks, and the capability to repair these damages declines with age. [128]
The hippopotamus does not produce pink milk, nor does it sweat blood. The skin secretions of the hippopotamus are red due to the presence of hipposudoric acid, a red pigment which acts as a natural sunscreen, and is neither sweat nor blood. It does not affect the color of their milk, which is white or beige. [52]
All animals have a set of DNA coding for genes present on chromosomes. In humans, most mammals, and some other species, two of the chromosomes, called the X chromosome and Y chromosome, code for sex. In these species, one or more genes are present on their Y chromosome that determine maleness.
DNA may be modified, either naturally or artificially, by a number of physical, chemical and biological agents, resulting in mutations. Hermann Muller found that "high temperatures" have the ability to mutate genes in the early 1920s, [2] and in 1927, demonstrated a causal link to mutation upon experimenting with an x-ray machine, noting phylogenetic changes when irradiating fruit flies with ...
In this way, our gender identity (the conviction of belonging to the male or female gender) and sexual orientation are programmed or organized into our brain structures when we are still in the womb. There is no indication that social environment after birth has an effect on gender identity or sexual orientation."