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1500 questions
49
votes
1 answer
What causes morning wood?
Sometimes men wake up with an erection in the morning. Why does this happen?
I J
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48
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1 answer
Why do human females have periods?
Why do human women have periods when most animals don't? It is known that the unfertilized egg needs to be shed from the uterus. But why shed the whole endometrium? Why didn't evolution put macrophages to work to simply digest the ovum and only the…
Harini
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48
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2 answers
Are there any animals that are both poisonous and venomous?
From my layman understanding, animals that inject venom into the bloodstream by biting or poking are venomous. And ones that harm you when you eat them are poisonous.
Are there any animals (or plants) that fit both descriptions?
I'm guessing eating…
Stephen S
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47
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2 answers
Why can't we kill ourselves by holding our breath?
Is it possible to kill yourself by holding your breath?
This question is obviously copied from Quora, but I had heard it as a fact that we cannot kill ourselves by holding our breath and I'm looking for a referenced answer.
Abhishek Choudhary
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46
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4 answers
Why is polyploidy lethal for some organisms while for others is not?
Polyploidy is the multiplication of number of chromosomal sets from 2n to 3n (triploidy), 4n (tetraploidy) and so on. It is quite common in plants, for example many crops like wheat or Brassica forms. It seems to be rarer in animals but still it is…
Marta Cz-C
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46
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2 answers
Are all emerging viral diseases of the past 100 years zoonoses?
From my basic understanding: The viruses causing Ebola, Sars and Covid-19 are all the result of a zoonosis, meanings that the viruses have passed from animals to humans.
So my question is: Are all recently (let's say 100 years) emerged viral…
NashVio
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46
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1 answer
What am I looking at in Franklin's Photo 51 of DNA?
Here's Rosalind Franklin's famous Photo 51, the X-ray diffraction image of DNA from which Watson and Crick deduced its structure:
My understanding is that it depicts a short segment of DNA shown from the side (so the axis that the strands wind…
Robert
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46
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2 answers
What is the function of epidermal ridges on human fingers (that produce fingerprints)?
What function is served by the epidermal or capillary ridges on human fingers, the supposedly unique impressions of which are known as fingerprints?
yuritsuki
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46
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2 answers
I just saw this bird outside my apartment. Anyone know what it is? (Texas, US)
Saw this bird outside my apartment in College Station, Texas and have never seen anything like it before!
It is about the size of a hand.
Rebekah
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46
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3 answers
What is the difference between orthologs, paralogs and homologs?
These three terms are often misused in the literature. Many researchers seem to treat them as synonyms. So, what is the definition of each of these terms and how do they differ from one another?
terdon
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46
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1 answer
What is it that creates that wonderful smell after a fresh rain?
I've heard that the wonderful smell of a fresh rain is actually chemicals released from the trees and grass and other plants.
What is the process that allows these chemicals to be released?
What are the chemicals that create that smell?
How is it…
SolarLunix
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46
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1 answer
Why do cockroaches flip over when they die?
This question has always mystified me since young. For beetles, I can reason that they flip over because they have a higher centre of gravity causing them to be in unstable equilibrium when they tuck in their legs when they are about to die. For…
Question Overflow
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3 answers
How does the sensitive plant detect vibrations?
The sensitive plant (Mimosa pudica) is a remarkable little plant whose characteristic feature is its ability to droop its leaves when disturbed:
Apparently, this ability to droop rests on the cells in the leaves of the sensitive plant being able to…
user132
45
votes
3 answers
Are humans more adapted to "light mode" or "dark mode"?
I was discussing with a colleague about using dark-mode vs. light mode and remembered an article arguing that humans vision is more adapted to light-mode rather than dark-mode:
I know that the trend “du jour” is to have a dark mode for pretty…
Alexei
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What was the breakthrough behind the “sudden” feasibility of mRNA vaccines in 2020?
Several sources describe the initial failures in the realization of a successful mRNA vaccine. E.g., this 2017 article from Stat describes the following problem faced by Moderna while working on one of their mRNA vaccines:
The safe dose was too…
hb20007
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