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[10] The first known mass extinction was the Great Oxidation Event 2.4 billion years ago, which killed most of the planet's obligate anaerobes. Researchers have identified five other major extinction events in Earth's history, with estimated losses below: [11] End Ordovician: 440 million years ago, 86% of all species lost, including graptolites
The timeline of human evolution outlines the major events in the evolutionary lineage of the modern human species, Homo sapiens, throughout the history of life, beginning some 4 billion years ago down to recent evolution within H. sapiens during and since the Last Glacial Period . It includes brief explanations of the various taxonomic ranks in ...
In some areas in England, a three-tier system of education is used, in which students pass through three stages: First school / Lower school ( Reception to Year 3/4), Middle school (Year 4/5 to Year 7/8) and finally High or Upper School (Year 8/9–Year 13) Key stage. Year. Final exam.
But a new study of nearly 5,000 9- and 10-year-olds found that sex and gender map onto largely distinct parts of the brain. A detailed look at children’s brains might show how sex and gender are ...
The chronology of the universe describes the history and future of the universe according to Big Bang cosmology. Research published in 2015 estimates the earliest stages of the universe's existence as taking place 13.8 billion years ago, with an uncertainty of around 21 million years at the 68% confidence level. [1]
In physical cosmology, the age of the universe is the time elapsed since the Big Bang.Astronomers have derived two different measurements of the age of the universe: a measurement based on direct observations of an early state of the universe, which indicate an age of 13.787 ± 0.020 billion years as interpreted with the Lambda-CDM concordance model as of 2021; and a measurement based on the ...
More than six million women in the United States, or 11 percent of women of reproductive age, become pregnant each year. More than half of these pregnancies, or approximately 3.4 million, are unintended, and 1.6 million of the unintended pregnancies are terminated through abortion.
The global average sea level has risen about 250 millimetres (9.8 in) since 1880. [1] Sea surface height change from 1992 to 2019 – NASA. The visualization is based on data collected from the TOPEX/Poseidon, Jason-1, Jason-2, and Jason-3 satellites. Blue regions are where sea level has gone down, and orange/red regions are where sea level has ...