What does it alive

We know the cycle of life: we are born, grow, become adults and do various things, including among our children, age, .. die.
Beyond chemical reactions, interactions of physical factors beyond everything that biology or genetics, man is much more. Analyzing every aspect of his life, and every part of his body: marvel. So well done! A perfect machine. Never man will not be able to reproduce it.
Yet what is life? What does it mean to live?

Imagine:

-Are old and sick. I 78. I struggle to go to the corner store to buy bread. When I was young fly immediately wherever needed. Now .... Of! I wear several times to manage something. Stairs to the second floor to the ground floor and creepy bother me. When I get down you must have a break to rest. Then up at the corner of the block, another fight. And winter is harder.
I look at my neighbors kid. 17 years old, and how long it takes me to go to the store and back it would certainly make 50 races. And this is just one example. Cry for strength and capabilities that I had when I was young. And then there is my health and shaky. I know that one day soon, I will close my eyes forever. BUT ... God ... I want a little ..... So, disease, pain, grief, wrestling with retirement and doing little for days hunger at home ...... and want to see tomorrow!
Sometimes I sit and look out the window. I think that no matter how much I have lived all want. I am aware that one day, all will end, but want a little. When I die I will not know anything. And sometimes I wonder why still being alive if I become a vegetable. But want to see colors, sounds to hear, to smell like the scent of flowers or even a good, to feel, to live.

This is the definition that we can give life: LIVE = see, hear, smell, feel, think. Can and without of them except 'thinking'. So THINK = LIVING.
So life is limited to essential needs. But human needs are:
Physiological,
-Affiliation,
-Love,
-To do something,
-Bequeath.
There are certainly many explanations from "what is life?" But the reality is that when you're ready to lose acknowledge best what it means to live.

One. Physiological needs. Are essential for survival: eating, drinking, sleeping, protect from cold and heat. There are also needs to feel, taste, smell, hear, see, etc.. They are the most important human needs. Their satisfaction is necessary to stay alive.
Two. Safety needs. Every human being needs to feel protected against any threat to life. To feel safe in their home territory in which she lives. Also a must is the sociability, that is to live in peace in a suitable environment with other people much like us and generally share the same ideals.
Three. NEED LOVE AND OWNERSHIP. Once basic needs covered, basic, this is the most important. Nobody can achieve as a person without being wanted and accepted by other human beings. This includes the need for friendship, family, belonging to a group, etc., or involvement in a non-sexual intimate relationship. Relationship with others at a deep emotional level is the usual form to meet this need. For example, family, spouse or friend. Lack of love and belonging can give occasion to mental imbalances.
April. NEED self-esteem. Every human being needs to respect herself and have a proper conception of his own person. It is about revenue recognition from others (resulting in feelings of power, prestige, acceptance, etc.) and of self-respect, which creates a sense of trust, suitability, competence. Unmet needs for esteem result in discouragement and long term inferiority complex. A autoestimare balance level (such as underestimating, for example, to think that the whole world is my higher) results in a low yield, and therefore, the deterioration of the behavior.
May. Need for self. According to Abraham Maslow, one in ten felt this intense need. The psychologist said that people who have it can increase their potential. They can seek knowledge, peace, esthetic experiences, self-fulfillment. Most revolve around the needs that can be provided. Self-Realization include higher and more abstract goals (eg justice, perfection, goodness, truth, individual decisions), which are more fragile, like top.