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Why are fearful stimuli more powerful at night?
For example, horror movies appear to be scarier when viewed at night than during broad day light.
Does light have any role in this phenomenon?
Are there changes in hormones at night versus during the day that makes fear stronger?
Mesentery
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What is the armpit hair for?
Modern human beings, especially women, cut their armpit hair. It seems to me the armpit hair is trivial/useless. Shortly speaking, what is the armpit hair for?
kiss my armpit
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Why are turtles classified as reptiles and not amphibians?
I understand that turtles are reptiles because like all reptiles, they have scales on their body. But turtles (specifically sea turtles) live on both land and water, very much like amphibians. Also, don't sea turtles have more of a moist skin unlike…
Irena
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Did the Great Oxygenation Event also cause a mass extinction?
It's usually assumed that the Great Oxidation Event around 2.3 billion years ago caused a great extinction of anaerobic life on earth. However, I was reading Nick Lane's book, The Vital Question, and he writes the following:
The 'oxygen holocaust',…
Daud
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What causes the range of severity of neurological deficits in Down's syndrome?
It's known that the severity of symptoms caused by a trisomy 21 varies from individual to individual. Part of the explanation for this range of severity is the finding that 94% of Down's syndrome sufferers have a full trisomy, ie., all of the cells…
AliceD
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Can Biologists identify all viruses?
I went to the doctor today with my girlfriend, and the doctor said that she had a virus but doesn't know which one and she should let the infection heal with some rest.
The fact that the doctor didn't know what type of virus she has bothers me.
Do…
Arthur Mamou-Mani
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How statistically significant was the "sweaty T-shirt" experiment?
An Overview of the Experiment.
In 1995 there was an experiment that involves young people smelling T-shirts worn by another gender and rating their preference. The researchers found that people preferred shirts belonging to people with a dissimilar…
James
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Why is human vision restricted to 400-700 nm?
Across the electromagnetic spectrum, 400-700 nm is a narrow spectrum of frequencies and focused in the region of short wavelengths. For example, radio waves cover a large range of frequencies unexploited by the visual system. So what biological…
HyperLuminal
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Selection for less efficient egg transfer in Human Botfly life cycle
I have heard that the Human Botfly transfers its eggs through other invertebrates, and it strikes my curiosity that if an insect could simply land on its host directly to deposit its eggs, then why have intermediate hosts?
I have speculated that the…
Galen
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How to understand influenza strain designations?
What do the strain designations for flu mean?
For example avian flu is classified as H5N1, what do the letters H, N and numbers 5, 1 mean? Is it more than a simple string-identifier?
aqua
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Is any known plant magnetic?
Is there a plant (not a microscopic type but one that is visible to the naked eye) that has so much iron (or magnetite), cobalt, or nickel in its body that it can attract a magnet?
In this case "attract" would mean that a person holding a small…
user12939
20
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Is this a grass cell?
I found this picture online claiming it was a grass cell. Clearly it is a cross section image but I was hoping you could tell me if this is actually grass, or something else if anything.
HBeel
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What is the healing process of mouth wounds?
When we have an external wound, blood generally tends to clot there, forming a layer of solid scab.
Yesterday, while brushing my teeth, I somehow hurt my gums and it got all bloody. However, it did not clot, neither did it hurt just after the…
The-Ever-Kid
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How and why did mammals go back to the oceans?
If I understand evolutionary biology correctly, mammals first evolved on land as small, rodent-like creatures, in a time when reptiles were dominant on land. Eventually, they diversified into the species we know today. Some of these species,…
HDE 226868
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How does isopropyl alcohol disinfect less in higher concentration?
Isopropyl alcohol (2-propanol) can be used as disinfectant.
For increasing concentration of it in water, the effect as disinfectant increases, and then decreases again.
Typical concentrations for use as disinfectant seem to be 60-75% isopropyl…
Volker Siegel
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