What is the most important physical or environmental factor humans could not live without?
1 Answer
The existence of liquid water
Explanation:
Liquid water is a universal solvent. Water is able to dissolve ionic and covalent molecules. The complex chemical reactions required for chemically based biological organisms, require water to activate and carry the components needed for the reactions.
Water has a unique property that as a solid it is less dense than water in its liquid state. This means that lakes, rivers, and oceans freeze on the top allowing living things to continue to thrive underneath the cold ice above. If water froze at the bottom as most substances, living things would not be able to survive in bodies of water than freeze.
Water has an unusual wide liquid range, of 100 degrees C. This is also important to living things. If life was based on a substance with a narrow liquid range, life could only exist in an environment with a constant temperature range.
While life depends on a wide variety of physical and environmental factors, in my opinion the presence of liquid water is the most important.
