These elements, as I see it, all have a common root or denominator(s) from which they are derived. The common root encompasses immutable facts that are more or less generalized, but cover widely known necessities that we as human beings all need in order to live, survive, and thrive. This common element is known as The Rule of 3, and goes something like this:

• 3 Minutes without Air
• 3 Hours without Shelter
• 3 Days without Water
• 3 Weeks without Food
• 3 Months without Love
• 3 Seconds without Hope

The Rule of 3 can be used to help prioritize human needs in order to continue living. Again, it is a generalization that is comprised in such a way so that it is easy to remember. Below is a brief interpretation of each.

3 Minutes without Air
Or oxygen, this means that most people can be denied oxygen is up to approximately 3 minutes. So this is cited first, because we all need oxygen to stay alive. We all need air to breath.

3 Hours without Shelter
That is 3 hours without shelter in extreme conditions. This length of time is generalized, and can be varied under a wide amount of circumstances, but think of a hail storm with golf ball-sized hail or a sand-storm....makes you want to run for cover, right. That is the human instinct to get out of inclement weather for protection. It makes sense to get out of high winds, rain, heavy snow, or high heat. The human body self-regulates its temperature but, cannot endure extremes of high or low temperature for long to work efficiently or stay alive.

3 Days without Water
This is another generalization, because it is known that people have survived up to a week or more without water. However, without water the body starts to systematically shut down and stop functioning.

3 Weeks without Food
There are records of humans going well past 2 months without food [1]. Out of immediate needs such as oxygen, shelter, and water, food is the one need we can go without the longest. As with all the needs cited above, the longer one goes without water, food, or shelter [in extreme high or low temperatures], the body and mind cease to function effectively, if at all.

3 Months without Love
Love and companionship are the two things that we may not immediately need to survive, but over time has proven vital in a survival situation to keep human beings going, even if all of the other immediate survival needs are met. Human beings are social animals, which means we survive and thrive as part of a group. People who do not feel that they belong often are victims of mental disorders such as chronic depression which often times can lead to suicide. Without the help of the group many people can not do things for themselves, or even function successfully; the saying "two heads are better than one", comes to mind under this element of need. Often having additional resources in the form of brain-power can help people figure their way out of a situation.

Some things to think on as it relates to the human need for love/companionship: A common form of punishment in the penal system is "solitary confinement". Also, often times when an opposing force conquers another the first step they take towards subjugation is the separation of men from women - it had been found that isolation from one another in captivity aids in the "breaking" of the captured.

3 Seconds without Hope
Hope, Spirit, or the Will to Live is THE most important element of survival. Even if all of the above elements are in short supply the internal desire to stay alive at all cost, or having a glimmer of hope - a chance to make it through is all that is necessary to keep going through even the most extreme adversity.

Mindset is 98% of the formula for survival. In fact, it is the prime ingredient for success in most anything in life. It does not matter if you can build 50 fires 50 ways with no matches or a lighter, or know all the edible plants in your region, or if you are a master tracker and hunter...if you have no hope or will to do any of those things you will perish. Conversely, only by education, and practice can one develop and forge the right mindset to stay alive no matter the circumstances.

In addition, I feel the cultivation of Hope is through having a strong connection with The Spirit, be that outside of one's self or within. I also believe that it also is cultivated from a sense of belonging and companionship, as I cited in the above element of Love.

The Core Elements
That was a brief synopsis of the element s of survival that make of the Rule of 3. Below are the core elements that should be remembered.

• 3 Hours without Shelter
• 3 Days without water
• 3 Weeks without Food

Three of the rules are left out in the presumption that there is ample oxygen, you are with a companion or will not be alone for too long, and of course you are keeping hope alive. Keeping these core basic rules and the order in which they are given will help you prioritize your needs should you find yourself in a survival situation.

Citation:
1). http://www.scientificamerican.com/article.cfm?id=how-long-can-a-person-sur