53 votes
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Can humans survive without consuming life?

The answer to your question is yes it is certainly possible. At one time it was thought that there was something special about "organic" chemicals which meant that they could not be artificially ...
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41 votes
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Why is it advised that infants are fed mother's milk?

The phrase "Breast is best" is a hotly debated one (source: The Guardian and personal communications with many folks). The reason why we don't want to feed infants cow's milk is, however, anything but ...
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36 votes

Can humans survive without consuming life?

Living organisms can be divided into hetrotrophs and autotrophs. Autotrophs like plants and algae are able to produce complex organic compounds from relatively simple inorganic components. They are ...
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  • 1,234
26 votes
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How can a drink contain 1.8 kcal energy while 0 g fat/carbs/protein?

The list of ingredients on the can mentions "Zuckerkulör," which is caramel colour, which can have 2 kcal/g, according to one producer. Next, there is "Citronensäure," which is citric acid, which can,...
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  • 7,969
20 votes

Can humans survive without consuming life?

Even on a purely synthetic diet, your body would still use living cells as an energy source. Our bodies contain more bacterial cells than human, mostly contained in our gut. These microbes process any ...
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16 votes
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How does zoo and laboratory animal feeding work?

I volunteered for 3 years at a large mammal laboratory where we diligently tracked the weight and caloric intake of each of our animals. Diets were weighed out each morning and total calories could be ...
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  • 306
15 votes
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Why do humans require vitamin B12 supplementation while herbivores do not?

The bacteria in the foregut of cud chewing animals (e.g. cows) provide enough B12 and other B vitamins. Uptake of B12 happens mainly in the small intestine. There are lots of bacteria in the human ...
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  • 1,405
14 votes

Can humans survive without consuming life?

Your question is phrased somewhat ambiguously as to whether you're asking about the theoretical possibility, the feasibility, or the practical ability in everyday life. 1) Theoretically, yes. It is ...
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  • 7,610
14 votes
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Why do carnivores evolve?

I'm going to focus on the why do carnivores exist part of this question, which should be extendible to answer why humans eat meat. Let's start a thought experiment in which we only allow the ...
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  • 16k
13 votes
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Where can you find the quantities of each amino acid of a particular protein or food?

There's a fantastic database available from the United States Department of Agriculture that includes almost 9,000 common foods, including their nutritional information. This database is searchable ...
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12 votes
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How long do fishes survive in a milk environment?

I can't support this answer with scholarly articles. But it's an interesting question if you think of milk as highly polluted water. Water from a tap (which is what goldfish usually live in) is '...
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11 votes
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How do large herbivores get enough protein?

It boils down to the anatomy. Herbivores are very good at digesting plant matter, which us monogastrics are not particularly good at. Many herbivores (such as ruminants) have large, highly developed ...
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  • 2,462
10 votes

Can humans transdermally absorb minerals from ocean water, and if so how much?

There is not very much transport of ions or water through the upper layer of the skin, mainly responsible for that is the stratum corneum (SC). Through this layer you will get only with small lipids ...
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10 votes
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How a vegan can consume all the needed varied proteins / amino acids?

Proteins are made up of amino acids. It isn't particular proteins that are necessary in diet, but particular amino acids. For humans, these come primarily from breaking down the proteins in foods we ...
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  • 36k
9 votes

Can humans survive without consuming life?

Depends on how you define "life"? Is unfertilized chicken eggs alive? What about cow milk? Well there are bacteria in it. What if you get rid of that bacteria? Then some people would not be able to ...
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  • 191
9 votes

What is the distinction between the terms detrivores, decomposers, saprotrophs and saprozoic organisms?

Detritivores consume (eat) detritus. Saprotrophs feed on dead organic matter by the means of extracellular digestion. Saprozoic organisms are protozoans that are saprotrophs. This actually comes ...
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9 votes
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Why cooked food considered nutritious if proteins decompose at much lower temperatures?

Cooking is just a form of digestion. What is digestion? Digestion is the process of breaking down big molecules into smaller molecules. When you cook food you break down big molecules into its ...
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9 votes
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What are 'acid stable' amino acids?

The amino acids asparagine and glutamine have hydrolysable amide groups on their R groups, as shown here: Note the leftmost amide group on both amino acids. When exposed to acid, these groups would ...
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9 votes
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Is palmitic acid really that dangerous?

Let's first clarify some concepts. Free fatty acids, including palmitic acid, are not present in animal tissues (or in the diet) to any large extent; they are esterified with glycerol to from ...
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  • 5,595
8 votes

Why is it advised that infants are fed mother's milk?

The contents of milk differ between species. For your example, cow's milk: Infants fed WCM [Whole Cow's Milk] have low intakes of iron, linoleic acid, and vitamin E, and excessive intakes of sodium,...
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  • 2,227
8 votes

Does food lose some of its mass in form of energy during metabolism?

Physics answer that is a bit silly If you want to be real technical about physics, mass and energy are the same thing, so any chemical bond that has some energy and is broken results in a change of ...
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7 votes

Can humans survive without consuming life?

Question: Is it possible for humans to live healthy long lives without eating any type of life, i.e no animals, no plants? First, according to a definition of a living organism(biology-online), milk ...
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  • 7,969
7 votes
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How do roots obtain nutrition?

One thing to remember when you uproot a plant is that some of the smallest structures break off most readily. What you will usually see after uprooting the plant are the largest parts of the root ...
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7 votes

What do bloodsucking animals actually feed on?

Lets find out how much calories are there in the blood. I am using this site for main reference, but will also add more references where needed. But before that, we should know that one donation of ...
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6 votes

Tap vs. mineral water for drinking

The mineral content in tap water differs from area to area as well as the source. The mineral content in bottled water is regulated by the companies that manufacture them, in particular the Mg and Ca ...
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6 votes

Is there a biological reason for spreading food intake into breakfast-lunch-dinner?

The three meals a day seems to be a cultural trait. Then what is the optimal number of meals a day? It is not known. Here are the results of some studies: Reduced meal frequency: It was found that ...
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  • 7,067
6 votes

Can humans survive without consuming life?

No. It is possible but extraordinarily impractical to nourish yourself without killing animals, plants or even bacteria, as many have explained in detail. However, your immune system constantly ...
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  • 4,470
6 votes
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Can carnivores survive on a (processed) vegetarian diet? Why or why not?

With arbitrarily broad meaning of "processed", yes. If absolutely nothing else, elemental purification and inorganic synthesis of something chemically resembling meat in nutrition is possible. ...
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  • 3,988
6 votes
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Nutrient limitation in terrestrial and freshwater ecosystems

The traditional explanation for this is that nitrogen compounds are more mobile than phosphorus compounds. As a result, nitrogen is more likely to flow through terrestrial ecosystems and accumulate in ...
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  • 166
6 votes

Where do mushrooms get their energy from?

Mushrooms are the fruiting bodies of fungi. Fungi get their energy by decomposing dead or decaying organic material, such as fallen leaves or dung. Some background: spores of fungi germinate forming ...
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