Instruct: Given a question, retrieve relevant documents that answer the question.
Query: How long can a human survive without water?
You can survive three minutes of severe bleeding, without breathable air (unconsciousness generally occurs), or in icy water. You can survive three hours in a harsh environment (extreme heat or cold). You can survive three days without drinkable water. You can survive three weeks without edible food.
The striking feature of this plant is that it can survive very long periods (months) without water and has adapted to survive the conditions of prolonged drought of its natural environment through an interesting physiological strategy – Drying up and rolling inwards to a ball in the absence of water, surviving several years of drought. When the humidity of the ground and the air starts to rise again, even after a long time since it has wilted, the plant then "resuscitates" after a period of desiccation (from a few days to several years) and it can continue its life cycle if it is hydrated again, recovering its photosynthesis and growth abilities perfectly. When it is "dead", its rooted leaves in the base become leathery, appearing dark brown or light brown to reddish brown.
Underwater microbial mats have been described as layers that live by exploiting and to some extent modifying local chemical gradients, i.e. variations in the chemical composition. Thinner, less complex biofilms live in many sub-aerial environments, for example on rocks, on mineral particles such as sand, and within soil. They have to survive for long periods without liquid water, often in a dormant state. Microbial mats that live in tidal zones, such as those found in the Sippewissett salt marsh, often contain a large proportion of similar microorganisms that can survive for several hours without water.
Finally, The Tick possesses something referred to as "drama power", or basically a tendency for The Tick's powers to increase as the situation becomes more dramatic. He can also survive in space without a suit, and under water without oxygen for "at least" a long time.
Vulcans are typically depicted as stronger, faster, and longer-lived than humans (although discrepancies have occurred—and although not as long as Vulcans, humans have been shown to live longer in the Star Trek universe than today—presumably as the result of advances in medical science). Vulcans are about three times as strong as an average human because of their home planet's higher gravity, although their durability is equal to humans. There are instances of them living over two hundred and twenty years. Having evolved on a desert world, Vulcans can survive without water for longer periods than humans. Vulcans can also go without sleep for as long as two weeks. Romulans are similar in appearance to Vulcans, with whom they share a common ancestry; they even appear almost identical on Starfleet sensors, with just a minute difference between them ("The Enterprise Incident").
The norovirus can survive for long periods outside a human host depending on the surface and temperature conditions: it can stay for weeks on hard surfaces, and up to twelve days on contaminated fabrics, and it can survive for months, maybe even years in contaminated still water. A 2006 study found the virus remained on surfaces used for food preparation seven days after contamination.
Fluid balance is an aspect of the homeostasis of organisms in which the amount of water in the organism needs to be controlled, via osmoregulation and behavior, such that the concentrations of electrolytes (salts in solution) in the various body fluids are kept within healthy ranges. The core principle of fluid balance is that the amount of water lost from the body must equal the amount of water taken in; for example, in humans, the output (via respiration, perspiration, urination, defecation, and expectoration) must equal the input (via eating and drinking, or by parenteral intake). Euvolemia is the state of normal body fluid volume, including blood volume, interstitial fluid volume, and intracellular fluid volume; hypovolemia and hypervolemia are imbalances. Water is necessary for all life on Earth. Humans can survive for 4 to 6 weeks without food but only for a few days without water.
Human survival on Mars would require living in artificial Mars habitats with complex life-support systems. One key aspect of this would be water processing systems. Being made mainly of water, a human being would die in a matter of days without it. Even a 5–8% decrease in total body water causes fatigue and dizziness and a 10% decrease physical and mental impairment (See Dehydration). A person on Earth uses 70–140 litres of water per day on average. Through experience and training, astronauts on the ISS have shown it is possible to use far less, and that around 70% of what is used can be recycled using the ISS water recovery systems. Similar systems would be needed on Mars, but would need to be much more efficient, since regular robotic deliveries of water to Mars would be prohibitively expensive (the ISS is supplied with water four times per year). Some experts have argued for setting up open-air settlements by using special construction methodologies- like excavating deep into the Martian crust to depths where air pressures may be sufficient to allow humans to survive without pressurized suits.Potential access to in-situ water (frozen or otherwise) via drilling has been investigated by NASA.
Farrant is investigating the ability of certain species of plants which are able to survive without water for long periods of time. As Farrant explains, "[a]ll plants have the genes that enable desiccation tolerance, but most use them only when they make seeds. Resurrection plants can also switch these genes on in their leaves and roots whenever drought occurs." The ultimate goal of her research is to find applications that will lead to the development of drought-tolerant crops to nourish populations in arid, drought-prone climates, notably in Africa, and her research may have medicinal applications as well. Farrant believes food crops which can survive long stretches without water "will become more important as climate change (increasing drought) continues to impact on agriculture."
Regardless of origin, climate and culture ultimately created the Arabian. The desert environment required a domesticated horse to cooperate with humans to survive; humans were the only providers of food and water in certain areas, and even hardy Arabian horses needed far more water than camels in order to survive (most horses can only live about 72 hours without water). Where there was no pasture or water, the Bedouin fed their horses dates and camel's milk. The desert horse needed the ability to thrive on very little food, and to have anatomical traits to compensate for life in a dry climate with wide temperature extremes from day to night. Weak individuals were weeded out of the breeding pool, and the animals that remained were also honed by centuries of human warfare.
The book gives tongue-in-cheek advice on how one can survive in the event that robots become too intelligent and rebel against the human race. "How to Survive a Robot Uprising" is partially based on scientific fact, and is a prime example of deadpan humor.
According to Tom Brown, the basic plan for survival is in the order of shelter (including clothing), water, fire, and food. Cody Lundin writes about the "Rule of 3s"; this relates to human survival without basics: three minutes without air, three hours without shelter, three days without water, or three weeks without food.
The difference between the culture of humans and the behaviors exhibited by others is that humans cannot survive without culture. Everything they see, touch, interact with and think about is cultural. It is the major adaptive mechanism for humans. They cannot survive winters in upper latitudes without protective clothing and shelter, which are provided culturally. They cannot obtain food without being taught how. Whereas other organisms that exhibit cultural behavior don't necessarily need it for the perpetuation of their species, they absolutely cannot live without it. 
In general, humans can survive for two to eight weeks without food, depending on stored body fat. Survival without water is usually limited to three or four days. About 36 million humans die every year from causes directly or indirectly related to starvation. Childhood malnutrition is also common and contributes to the global burden of disease. However global food distribution is not even, and obesity among some human populations has increased rapidly, leading to health complications and increased mortality in some developed, and a few developing countries. Worldwide over one billion people are obese, while in the United States 35% of people are obese, leading to this being described as an "obesity epidemic." Obesity is caused by consuming more calories than are expended, so excessive weight gain is usually caused by an energy-dense diet.
Groundwater can be thought of in the same terms as surface water: inputs, outputs and storage. The critical difference is that due to its slow rate of turnover, groundwater storage is generally much larger (in volume) compared to inputs than it is for surface water. This difference makes it easy for humans to use groundwater unsustainably for a long time without severe consequences. Nevertheless, over the long term the average rate of seepage above a groundwater source is the upper bound for average consumption of water from that source.
A human being can survive an average of three to five days without the intake of water. The issues presented by the need for water dictate that unnecessary water loss by perspiration be avoided in survival situations. The need for water increases with exercise.
Space medicine is a developing medical practice that studies the health of astronauts living in outer space. The main purpose of this academic pursuit is to discover how well and for how long people can survive the extreme conditions in space, and how fast they can re-adapt to the Earth's environment after returning from space. Space medicine also seeks to develop preventative and palliative measures to ease the suffering caused by living in an environment to which humans are not well adapted.
Water is an absolute necessity in human sustainability and human survival. There is no human activity that can be sustained without the use of water whether it be at a direct or indirect level. The United Nations declared access to water as a fundamental basic human right under articles 11 and 12 of the International Covenant, which identifies and protects rights at an international level. In addition, the Millennium Development Goals of 2000 includes the sharing and fair allocation of water as a major goal. The United Nations and Millennium Development Goals oppose water privatization because water is a human right and every human being is entitled to water use. Equal access to water entails that no individual should be given privilege over the other at the absolute basic level. The sale of water cannot be permitted or justified under the United Nations at the basic level because water is seen as a universal human right. The right to water was created specifically to assist poor individuals in developing countries through attaining equitable access to water to prevent illness and death. Additionally, water rights are also associated with protecting the environment, strengthening the economy and strengthening the water delivery system.
"Galba truncatula" is amphibious organism and can survive long dry periods. This is caused by its high ability to aestivate during drought conditions. It is known that "Galba truncatula" can survive 6 weeks to 4.5 months of dry periods in aestivated stage in mud. In the laboratory cultures, Kendall (1949) observed survival over 1 year in Petri dishes without water.
There are distinct parameters for who is eligible for transplantation of the different organs. Broadly speaking (this is not meant to be exhaustive), these include: age, how long they have been on the waiting list, how urgently they need the organ (which is often related to how long they've been on the list, and whether they are actually in end-stage disease, which has its own laboratory and functional criteria per organ); their prognosis (how stable they are now- whether they can survive major invasive surgery and the anesthesia and post-op period, and how they have been, and how they likely will fare with and/or without the organ, versus with other therapies that are not transplantation- such as continued dialysis or getting an artificial heart or left ventricular assist device). 
Chemical control is the least used out of the three controls of water hyacinth, because of its long-term effects on the environment and human health. The use of herbicides requires strict approval from governmental protection agencies of skilled technician to handle and spray the affected areas. The use of chemical herbicides is only used in case of severe infiltration of water hyacinth. However, the most successful use of herbicides is when it is used for smaller areas of infestation of water hyacinth. This is because in larger areas, more mats of water hyacinths are likely to survive the herbicides and can fragment to further propagate a large area of water hyacinth mats. In addition, it is more cost-effective and less laborious than mechanical control. Yet, it can lead to environmental effects as it can penetrate into the ground water system and can affect not only the hydrological cycle within an ecosystem but also negatively affect the local water system and human health. It is also notable that the use of herbicides is not strictly selective of water hyacinths; keystone species and vital organisms such as microalgae can perish from the toxins and can disrupt fragile food webs.
"How to Survive" is played from a top-down perspective. There are two game modes, story and challenge, and both can be played with up to two players. Challenge mode puts the player(s) on one side of the island, and they must get to the other side, where their getaway vehicle awaits. The player's mission is to gather materials, craft weapons, and make it off the island without dying. Neither challenge or story are timed, and therefore, the player can take as long as they want.
The "Dungeoneer's Survival Guide" includes new proficiencies, as well as ideas for the creation of underground adventures. Characters gain proficiencies by way of "non-weapon proficiency slots", which can be filled with a variety of secondary skills. This book also provides rules on actions such as how well non-thieves climb walls and trees, how far characters can leap across chasms, and how long characters can hold their breath under water.
"Champaign ILL" is described as examining how "every rapper has a crew he can't live without...and vice versa" and exploring "how long the crew can survive without being in the limelight."
The unit is often used to describe how much water rainwear or other outerwear can take or how much water a tent can resist without leaking.