This tag is for questions about the general biological features of human beings (as opposed to the biology of non-humans).

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Can bigger persons generally resist g-forces better?

I've seen a claim that bigger persons generally resist g-forces worse than smaller in an undergraduate biology book. However this claim was supported by the argument that blood has to travel a longer ...
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0answers
21 views

Why Do Bruises Change Colors? [on hold]

The bruses 1st have a red colour which is understandable. but later several blue , yellow , slightly greenish and brown also? How does the colour changes ?
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23 views

Why do we pass out when we are under attack?

It is known that we might pass out, but not die, when we are under attack, e.g. got striken at the neck, blown by blunt object at the cerebellum etc. Wouldn't it be more "advantageous" to be conscious ...
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1answer
7k views

Ramifications and possibility of a diet consuming exclusively of human semen

Semen is a thick, nutritious liquid, rich in vitamins (such as C, B12), amino acids, lipids, monosaccharides (fructose), et cetera. Can semen's ability to fulfill the needs of human organism provide ...
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1answer
31 views

Why Do we close our eyes while sneezing?

Google says germs may fall on eyes from our sneeze but it happens all the time . Also it says it a part of contraction. What may happen if we sneezing wirh our eyes open ?
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0answers
43 views

Can our eyes see faster? [closed]

There are some animals that react faster than normal rate (like flies, etc). I guess it's because they can see faster than other animals and humans, as if time passes slower for them. I think some ...
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0answers
20 views

Twin pregnancy, one natural, one surrogate, is it possible? [on hold]

Looking for any case study or biological reason why the following would / would not be possible: Couple A creates and stores a frozen embryo Couple B gets pregnant naturally Couple B then, without ...
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0answers
14 views

Is it better to eat something that is more or less related to humans?

My question is, would it be better to eat something like a sea cucumber or would be it better to eat a chimpanzee? Maybe this isn't a dichotic answer. Is it better to eat something in between, like ...
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1answer
47 views

Do we all dream “every” night? [on hold]

I had an argument with my brother and he claims that he doesn't dream every night ie when he dreams he always remember and if not he hadn't dreamt at all. I'm under the impression that all humans ...
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1answer
443 views

Why do people and animals stretch out their bodies and what is causing this behaviour?

I noticed that my cat which is only 6 months old has started stretching its body from time to time. Then I thought that this motion doesn't seem very natural from another cat's viewpoint, so my cat ...
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29 views

What options are there to consume water and can you survive on them alone?

I thought about this a while, i can think of several ways, but i am not sure if there are other options and if you can survive on them alone withou dying of dehydration (lets ignore other problems ...
2
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1answer
23 views

How is pain induced by blunt and sharp objects?

Normally, when something touch you, you won't feel pain. With a great force "touching" you, you will feel pain. However, if something that is spiky makes contact with you, you will feel pain. So, how ...
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1answer
99 views

Do our belly buttons consist of scar tissue?

I read an interesting post on Facebook the other day saying that we all have a visible scar since birth - our belly button. This got me thinking (and research for me only found results regarding belly ...
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2answers
68 views

Is there a way to prevent an HIV infection after exposure to HIV infected Blood?

If a person is accidentally injected with blood from an HIV+ person, is there a treatment option that can keep the person from developing an HIV infection?
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0answers
14 views

Why I don't feel pain when I press the skin on my knee and elbow?

Does the muscle on our knee and elbow have some speciality ? Why are we unable to feel any sort of pain when I pinch it ? I also did it with my Mom and Dad and result was same .
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1answer
20 views

What are the changes to semen if it is put stationarily in the atmosphere for a period of time? [on hold]

If I put it in a test tube for, say a week, what are the physical and chemical changes? In addition, will the fructose inside be lost or broken down?
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1answer
28 views

During Orgasm, Do females ejaculates like males? [closed]

Acc to Bio-Science, males get ejaculates when they reach orgasm, so what about females? do they get ejaculation like males?
3
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0answers
62 views

Why are lips covered with specialized skin?

I found out some interesting facts while studying our lips: They are covered in glabrous skin, while most of the skin surface is hairy; The outermost layer (stratum corneum) of the skin is far ...
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0answers
27 views

If humans are 10cm taller than 200 years ago, then how can it be that we are “not much different” from humans 70000 years ago? [closed]

According to Yuval Noah Harari in his book "Sapiens: A Brief History of Humankind" we today are not much different from the post-cognitive-revolution Homo Sapiens which lived 70000 years ago. But then ...
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1answer
23 views

Marker validation using transcriptome and genomic sequences derived from a single cell

I conducted a SSR marker analysis using bioinformatic tool on some RNA-seq data of human tissues. Now, my supervisor believed that we have to validate these SSR on a transcriptomic and genomic ...
14
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1answer
2k views

Why does hair turn grey or white, and why does it happen later for some?

The question is pretty simple: what is happening molecularly when hair turns grey or white? I would imagine that it is due to the lack of a particular compound. I'm also interested in why some ...
9
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2answers
184 views

Should we induce fever to assist healing?

I am currently reading "The Fundamentals of Anatomy Physiology" 10th edition, and have found it an incredibly interesting book. I have just been reading about the lymphatic system, and the various ...
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0answers
13 views

Proteins denaturation and natural selections

Which are the advantages, in terms of natural selection, of the denaturation of the proteins during the food preparation? Or in other terms, is it more important the reductions of bacteria in the food ...
2
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1answer
42 views

Do the enzymes and compounds in saliva help with stain removal?

Does spitting on stains help with removal? Saliva is high in amylase that should help with the breakdown of protein rich stains like blood and semen. It also contains antimicrobial enzymes and ...
5
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2answers
436 views

Why can humans feel electricity?

What evolutionary process has provided humans with the ability of feeling electric current? Besides lightning and electric eel, what natural hazards include electricity that poses a threat to humans? ...
3
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1answer
53 views

Why do men grow facial hair?

Ancestral facial hair. Our closest ancestors, the chimpanzee and bonobo, both grow facial hair around the mouth area. What is noteworthy is that this is the case in both males and females of the ...
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3answers
513 views

Why we do not get hurt from HCl secreted in the stomach?

I read in my book that during digestion our stomach secretes hydrochloric acid ($HCl$). Why we do not get hurt from it? It was also said that mucous provides protection, but from where is it coming?
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11 views
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41 views

Why do we turn darker in the sun?

I tried the all powerful google to answer this question - but I am not getting the answer I seek. I know we turn darker because the skin produces melanin. The question remains - why darker? I am a ...
5
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2answers
201 views

How do gory images lead to nausea?

How do gory images lead to nausea? Yesterday my friend visited shock sites (a website). He said that he got nauseous sensation within seconds after viewing the gory images. However, I don't ...
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0answers
21 views

How late in a human pregnancy can a zygote split?

This page indicates that the first two days is "very early" for a zygote to split, and that conjoined twins are the result of an "extremely late" split: If the zygote splits very early (in the ...
2
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2answers
54 views

Can the human body enter “Power Save” mode? [closed]

Once a year, I am fasting for 24 hours. No food or drink at all for whole 24 hours. Recently I thought about what is happening to me during those 24 hours, and realized there might be something ...
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1answer
48 views

Cancer in myogenic heart cells?

Why cancer does not occur in myogenic heart cells? Is there any special ability in heart cells to resist cancer ?
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3answers
77 views

Why didn't humans evolve to reproduce identical twins all the time?

According to the selfish gene theory, it seems like because identical twins sometimes get produced, a mutation to a gene that says, "if you have an identical twin, be fully altruistic towards them" ...
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1answer
70 views

Why do sneezes come out the mouth?

As anyone who's ever sneezed can tell you, it's caused by irritation in the nose. And the answer to a question on this very SE attests that "sneezing is a reflex, partially autonomous, to clear the ...
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31 views

Proteins and Blood Acidification

Is there evidence to suggest that excessive consumption of Whey, or similar proteins will lead to acidification of the blood?
6
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2answers
2k views

How hot can a beverage get without burning the tongue?

What is the maximum temperature that a beverage can be without burning the tongue? I suspect there's a maximum temperature that the surface tissue of a tongue can withstand without being damaged ...
4
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2answers
32 views

How can a chromosome translocation in somatic cells lead to disease?

Looking at this picture... ...I get the impression that the part of chromosome is attached to other chromosome, but it is not mutated. When we assume that all genes in the translocated part are ...
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1answer
50 views

Cut strand of hair longevity?

Quick and useless question : what can be the longevity of a cut strand of hair, assuming we kept it in (good) normal conditions ? Any idea ?
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1answer
30 views

Does alcohol really do more damage to the body of a child compared to an adult?

Beside the fact that children and teens (people under the age of 18 year) usually have less body weight than the average adult, is there a biologically fundamental difference between the damage done ...
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0answers
25 views

How does drug-induced photosensitivity work?

Some drugs (tetracyclines, for instance) can cause photosensitivity reactions—that is, some patients become extremely sensitive to the sun, developing rashes or inflammation after spending time ...
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1answer
51 views

How long do human egg cell grow up?

I read article about alcohol harm where written that child may bear with birth defect cause mother used to drink alcohol 10 years ago so egg cell stay damages that long. I don't believe that human ...
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1answer
22k views

Can a person really die quickly from biting their tongue?

A common trope in certain circles (like Eastern martial fiction), is someone committing quick suicide by biting his or her tongue. But is this really possible? The internet turns up millions of ...
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63 views

How to mimic / approach some animals/insects' anabolism?

This article states that some shelled animals - spiders, scorpions, crabs, worms and other creatures - have metal atoms in their claws, jaws and fangs. I believe through anabolism, since they eat ...
19
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1answer
5k views

What do you see when your eyes are closed?

If you are in pitch black and you close your eyes, you sometimes can see strange shapes of various colors. A lot of the time these shapes and colors change as you observe them. This phenomenon still ...
3
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2answers
57 views

Why are our bodies created to itch when histamine is released by our immune systems?

Why do bug bites and cuts itch when scratching them clearly doesn't help us survive? Did our early ancestors need to rely on this itching sensation, or is it just that the receptors for itches just ...
2
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2answers
51 views

Database of medically validated SNPs

I'm looking for all possible sources of clinically tested human SNPs. There is a handful of databases that store SNPs (like dbSNP), but I only need those that have validated presence/absence of ...
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3answers
4k views

Is it possible for a child to grow taller than their tallest parent?

I have heard that offspring can't grow taller than either of their parents but I've also heard that sometimes some gene activation can skip generations. Is it possible for a child to grow taller than ...
6
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1answer
169 views

How to identify the age of a “living” person?

Different people may age differently. A 60-year old person may appear to be 80, while somebody else could appear younger than their mathematical age. Some other people may have progeria. What is ...
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0answers
23 views

Why does our body exhibit bilateral symmetry? [duplicate]

Externally, we (humans) look symmetrical. However, internal organs don't show the same patterns of symmetry (heart being on the left side while the liver is on the right side, etc.). It is a bit ...