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70

You must tell facts from fiction; viruses need living cells to replicate because they do not have the molecular machinery at hand to generate energy and construct building blocks essential to life. So no, viruses cannot bring back the dead or revitalize dead cells. One thing that comes close to it are the so-called zombie ants. These ants have been ...


57

Short answer Healthy people cannot hold their breaths until unconsciousness sets in, let alone commit suicide. Background According to Parkes (2005), a normal person cannot even hold their breath to unconsciousness, let alone death. Parkes says: Breath‐holding is a voluntary act, but normal subjects appear unable to breath‐hold to unconsciousness. A ...


35

Counterexample: At least some people can train themselves to hold their breath until they pass out, and if this occurs underwater they will almost certainly die by drowning. When I was in military service I became friends with some U.S. Navy SEALs. They go through a notoriously difficult training and selection process (BUDS) that has been well documented. ...


22

There are multiple levels of memory, some of which would die immediately, some of which would take some time. So the answer is: it depends; some immediately, some only very slowly. At the highest level, the current neuronal firing state of the brain encodes memory on a very short scale - working memory. The memory held on this level does not have a clear ...


20

The immortal jellyfish can revert back to its immature polyp stage after reaching maturity, then mature again, over and over. You can read more on the wikipedia page, but this ability means it can potentially avoid senescence altogether.


19

Short answer Between 62,000 and 63,500 feet (18,900 and 19,350 meters) blood begins to boil at body temperature. This altitude, referred to as the Armstrong limit, is generally considered to be the absolute limit compatible with life. At this point, humans cannot survive without pressurization measures. Background Atmospheric pressure drops at higher ...


17

Long story short, the astronaut probably wouldn't make it, and would first loose consciousness then suffocate. There is a lot of myth and hollywood dramatization regarding this kind of thing. Here are some: You will explode. This is just ridiculous. The skin is air tight (relatively speaking). It is also very elastic and can pull and bend quite a great ...


16

Yes, it can, but it is extremely rare. ... nosebleeds are rarely fatal, accounting for only 4 of the 2.4 million deaths in the U.S. in 1999 [1]. The main issue is that epistaxis can be a sign of potentially fatal diseases: The instances in which nosebleed is potentially fatal are those in which there is a history of recent head injury, severe ...


15

Snopes.com gives a discussion of possible issues with the original experiment. Evaporation or bowel or body movements for instance. I think the biggest complaint about the experiment is that it has not been reproducible and that the original experiment was flawed. MacDougall only took six measurements and he threw two of them out in his original work. ...


12

About 52 to 74 days according to hunger strike wiki page. This wiki page bases its data on 8 persons who died due to hunger strike: Days survived by each person: 66, 59, 61, 61, 61, 46, 71, 73, 62, 60.


11

Nope, you wouldn't die instantly. While explosive decompression has never been tested on humans (for obvious reasons), the dangers of a vacuum have mostly to do with the pressure differential between your body and the now pressure-less void around you. The most fragile parts of the biological system would be the lungs and ears, and the instantaneous ...


11

Two compounds are specifically associated with the smell of decaying cadavers (Hoffman et al., 2009), namely: 1,5-pentanediamine (cadaverine), and 1,4-butanediamine (putrescine) Cadaverine is produced by breakdown of lysin and putrescine by the breakdown of ornithine (Science ME). Both are nitrogen-rich compounds and particularly pungent-smelling. ...


10

(source: free.fr) Alain Bombard He is a french biologist who voluntarily tested how many days a man can survive drinking seawater and how? Biologist point of view Sea contains ~3.5% of salt$^1$. Our kidney separates the waste from water and excrete them in urine provided the salt content is less than ~2%.$^2$ So, it will take the water already present ...


10

Note: This answer is a complement to @AliceD's answer, and is partly reusing stuff from this related answer. Since you are specifically asking about viruses, I thought that it might be interesting to mention that similar behaviour changes as those mentioned for fungi can also be caused by viruses. See e.g. this quote from Roy et al. (2006): In many cases ...


10

Eating the dead makes far more likely you will catch whatever killed them. They transport and dispose of the dead for the same reasons we do, to reduce disease vectors. They dispose of their garbage for much the same reason, in fact they often dispose of both in the same place even if they separate the two in distinct piles. Hygiene is very important is ...


7

This would vary a LOT depending on the amount of stored fat, previous diet, the weather and even the water drunk. Weeks though there is a good chance that a loss of electrolytes can cause health problems. (that's why I mention the water you drink, because many bottled water brands and wells have a bit of salt in them.) Its hard to say from anecdotal ...


7

One other important event that can kill the person is that the atmospheric pressure on Mars surface is less than one percent that of earth at ground level. Suddden exposure to extremely low atmospheric pressure will immediately release dissloved gases within blood and and other body fluids as bubbles and the individual is likely to get a very severe form of ...


7

You will be hard-pressed to find any scientific data on this question. Psychology in humans is already a difficult study, at times failing to demonstrate results with real scientific rigor. When studying animal psychology, you face another substantial barrier - language. Although some primates have been taught to communicate with sign language, the best of ...


7

I don't exactly know what you meant to say by "non-functional". Red blood cells are delivering oxygen to tissues, but they cannot do this anymore in the lack of blood flow. White blood cells degenerate and after about 84 hours are no longer existing as cells (Babapulle CJ, Jayasundera NP, 1993). Neutrophiles degenerate first and lymphocytes last. Platelets ...


7

Rigor mortis does not cause movement. It causes rigor (Latin for stiffness.) This is only a comparison, but think of it this way. Superglue doesn't shrink or change the shape of the connection of the two things glued together; it just holds them there with powerful 'stiffness'. So imagine that at death, part of our muscle cells exuded superglue. You would ...


6

Once the thermodynamically irreversible processes we call brain-death have occurred both memories and the machinery to retrieve them are lost. This is not an answer but a cavil with the premise of the question. Challenges that do not destroy the brain itself are different from those that do. In particular there may be a big difference between hypoxia ...


6

Any injury, that results in external bleeding can lead to death, since it is a breach in the body's defenses and an entry point for pathogens. Explanation: When you have nose bleeding the blood must be coming from somewhere. Usually from inside your body. That means there is a hole in your body which is big enough for blood to stream out. That in return ...


6

The issue I suspect you are struggling with is the anthropomorphization of the evolutionary process. Evolution is an optimization process driven by random mechanisms...i.e. there is often not a "reason" for why certain things are the way they are. Evolution is not a conscious "designer" that produces things with a specific goal in mind...it simply "picks" ...


6

I very much doubt it. You may however die from whatever's causing the pain. The reason you feel pain is so you stop doing whatever is causing the pain. Hence someone knows not to touch a hot fire because it is painful. But the pain itself is not actually the danger - it's the fire burning away skin. So pain is actually a good thing, a survival mechanism. So ...


6

You have a very interesting question there! In order to answer, however, we must examine the most widely accepted "reason" for why we age and eventually die. Most scientists agree that it is because of mass cell death. Normally you and I would be able to deal quite well with mass cell death (such as a very large injury), the problem comes in when we are ...


6

Second law of thermodynamic and ageing The second law of thermodynamic applies to closed system. Organisms are not closed system. The second law of thermodynamic is a fundamental principle of our universe and any biological processes do follow the principles of physics. However, stating that biological ageing is (partially) caused by the second law of ...


6

Yes. Moreover, even if they were not urinating at the time of death, they likely would at death, assuming adequate filling of the urinary bladder. There are two sphincters that close off the urethra. One is under control of the autonomic nervous system and the other is voluntarily controlled (somatic). At death, both sphincters will relax, releasing the ...


6

I'm not sure I agree with that, but if I had to support that assertion, I would say that while patients with COPD, CHF and neurodegenerative diseases may die of hypoxia (no fever there), patients with cancer more often die of opportunistic infections. In patients being treated with chemotherapy (and for some time afterwards as well), myelosuppression - that ...


6

We don't know. More precisely, we know of many, many different reasons why the immune system deteriorates with age, but we don't really know which are different measures of the same thing, which are independent factors, which factors actually cause problems and which are harmless and incidental, and so on. There are too many age-related phenomena to ...


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