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Life is the characteristic state of organisms and individual cells. Properties common to the known organisms found on Earth (plants, animals, fungi, protists, archaea and bacteria) are that they are carbon-and-water-based, are cellular with complex organization, undergo metabolism, possess a capacity to grow, respond to stimuli, reproduce and, through natural selection, adapt in succeeding generations.
An entity with the above properties is considered to be organic life. However, not every definition of life considers all of these properties to be essential. For example, the capacity for descent with modification is often taken as the only essential property of life. This definition notably includes viruses, which do not qualify under narrower definitions as they are acellular and do not metabolise. Broader definitions of life may also include theoretical non-carbon-based life and other alternative biology.
Although it cannot be pinpointed exactly, evidence suggests that life on Earth has existed for about 3.7 billion years . Currently the entire Earth contains about 75 billion tons of biomass (life), which lives within various environments within the biosphere
Although there is no universal agreement on the definition of life, scientists generally accept that the biological manifestation of life exhibits the following phenomena:
Homeostasis: Regulation of the internal environment to maintain a constant state; for example, sweating to cool off.
Organization: Being composed of one or more cells, which are the basic units of life.
Metabolism: Production of energy by converting nonliving material into cellular components (synthesis) and decomposing organic matter (catalysis). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life.
Growth: Maintenance of a higher rate of synthesis than catalysis. A growing organism increases in size in all of its parts, rather than simply accumulating matter. The particular species begins to multiply and expand as the evolution continues to flourish.
Adaptation: The ability to change over a period of time in response to the environment. This ability is fundamental to the process of evolution and is determined by the organism's heredity as well as the composition of metabolized substances, and external factors present.
Response to stimuli: A response can take many forms, from the contraction of a unicellular organism when touched to complex reactions involving all the senses of higher animals. A response is often expressed by motion, for example, the leaves of a plant turning toward the sun or an animal chasing its prey.
Reproduction: The ability to produce new organisms. Reproduction can be the division of one cell to form two new cells. Usually the term is applied to the production of a new individual (either asexually, from a single parent organism, or sexually, from at least two differing parent organisms), although strictly speaking it also describes the production of new cells in the process of growth.
2006-12-04 17:45:26
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answer #1
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answered by mallimalar_2000 7
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Good question, it helps us think...
"What is Life's most important question?"
My answer to this is. What have I done in my life or am doing that will make a difference in someone else's life for good?
Volunteering time and effort is a great way to answer this question on a regular basis.
I think something good to add to this is...
"What am I thankful for or grateful for in my life today?"
Repeat this question every day.
Always having a heart full of gratitude is really big!!!
2006-12-05 01:52:53
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answer #2
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answered by Cat 3
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Life's most important question is What's your purpose in life ?
Life is not mainly study, graduate, getting good job, got married, having children and end..
Everyone has their special role and task in life.
2006-12-05 02:15:32
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answer #3
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answered by Cookie 1
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Why are you here? What importance do you have on others? All of us are here for a reason. To teach others, to love to learn.
2006-12-05 01:38:02
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answer #4
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answered by queenmaeve172000 6
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WHICH OF THESE BIG QUESTIONS CONCERNS YOU MOST?
What is the meaning of life?
Is God to blame for our suffering?
What happens when you die?
Find the Bible’s answers to these questions at jw.org.
2014-08-05 12:04:18
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answer #5
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answered by deafinfo 1
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How can I live the Golden Rule"
2006-12-05 01:38:58
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answer #6
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answered by devora k 7
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Where can I bring Love where Love seems not to be, next?
2006-12-05 01:38:04
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answer #7
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answered by Richard15 4
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what do you contribute to the world? how did you spend your time on earth, wisely or poorly??? those questions.
2006-12-05 02:53:15
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answer #8
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answered by westcanuck 1
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Is your soul ready to meet it maker?
2006-12-05 01:39:20
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answer #9
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answered by sparkle 1
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Are you loved by anyone, other than family, for being yourself?
2006-12-05 01:38:05
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answer #10
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answered by Anonymous
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