Answer:
When microbiological media has been made, it still has to be sterilized because of microbial contamination from air, glassware, hands, etc. Within a few hours there will be thousands of bacteria reproducing in the media so it has to be sterilized quickly before the microbes start using the nutrients up.
Media for growing bacteria and cells is sterilized before use to prevent the contamination of the desired culture with other types of bacteria or cells. The presence of undesired cells on culture media can lead to the failure of the culture or affect the results of future experiments.
Bacteria and cells are often grown on culture media to determine the presence or absence of specific bacteria or types of cells, such as pathogenic bacteria or abnormal cells that may indicate disease. Cells may also be cultured as part of an experiment to determine if a particular experimental factor has affected the ability of a bacterium or cell to grow. In both cases, the presence of microorganisms other than those that are intended for culture in the culture medium may cause the culture to fail, as the undesired bacteria or cells can out-compete the desired cells for the nutrients in the culture medium.
Explanation:
Measured edge to edge, the universe as we know it stretches some 93 billion light-years across. That unfathomable expanse contains 2 trillion galaxies, each shining with millions of stars and dotted with more planets than you can imagine. Given all that real estate, it seems unlikely we're alone. Yet in all of human history, we've found nothing to suggest otherwise.
Scientists who have spent their careers searching for any sign of an otherworldly civilization concede it’s possible we’ve got the cosmos to ourselves. Still, they highly doubt that’s the case. “To say this is the only place where there’s any intelligence is hubris of a very high order,” says astrophysicist Seth Shostak of the SETI Institute. (The acronym stands for “search for extraterrestrial intelligence.”) Statistically speaking, there are too many locations where life could thrive for humanity to be an anomaly.
Astronomer Frank Drake suggested as much in 1961. He posited that the number of technologically advanced civilizations in our galaxy would be the product of seven variables. They include the number of stars throughout the Milky Way, how many of those bright, burning gas balls illuminate planets, and what percentage of those worlds could support life. His eponymous equation was a thought exercise meant to start a discussion among colleagues, but it has helped frame the topic in the years since he wrote it.
Many of Drake's variables are speculative, making his math little more than conjecture. But astronomers now know for certain that exoplanets, many of which could harbor life, form throughout the Milky Way like dust bunnies under your couch. In the past two decades, researchers have confirmed the existence of more than 4,000 planets in our galaxy, a finding that suggests the cosmos all but brims with them. Astrophysicist Christopher Conselice of the University of Nottingham puts the number at 100 quintillion. That's a one with 20 zeros. Some think there may be far more than that.
cheater:
hey u said 20 points but there its mention 10 points, what do u think am i mad
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Look at the board ! => Blick auf die Tafel !
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Listen => hören !
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Open the windows ! => öffnen Sie die Fenster !
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Close the door ! => schließen Sie die Tür !
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Repeat (v) ! => w<span>iederholen !
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Stand up ! => aufstehen !
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Silence (n) => Stille (die)
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Take out your books ! => nehmen Sie Ihre Bücher !
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<span>Pack away your things ! => </span>wegpacken Sie Ihre Sachen !
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Sit down ! => hinsetzen !
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GUTEN TAG !
