Living beings normally cannot exist more than a few kilometers below the surface of the earth, or more than a few kilometers above it. Life occupies an incredibly thin ‘skin’ at earth’s surface. This is known as the biosphere.
The most significant of all forms of physical conditions is proper lighting because bad light causes eye-strain and fatigue to workers. There are two sources of light like natural light and artificial light. Natural light is the best form of light from the point of view of health and efficiency of the worker.
Charles Robert Darwin in his book ‘Origin of species’ by Natural selection gave a beautiful theory on evolution. His theory of Natural selection can be summarized as follows:
Charles Robert Darwin published his theory of natural selection in his book ‘Origin of Species’ in 1859. Due to extreme popularity of the theory he is called ‘Father of the Evolution’ and his ideas are known as Darwinism. Darwin based his theory on certain observable facts and deduced some principles.
The difference between Natural System and Phylogenetic System is in Natural system Classification based on form and natural relationship among plants whereas in Phylogenetic system classification based on natural, evolutionary and genetic relationship among plants.
The differences between Artificial system and Natural System are:- in Artificial system classification occurs without basing on relationship among plants whereas in the later classification occurs on form or natural relationship between plants.
Commonly, two broad classes of sources of water pollution are recognized. One is 'point pollution sources, where the source is a well-defined location, e.g., a sewage outlet or a factory drain, the pipe through which factory discharges its waste water into streams.
Useful facts about natural calamities and role of individuals and community 1. India often faces natural calamities like floods, cyclones and droughts in different parts of the country. 2. By being well-informed and having the ability to respond quickly to a natural calamity, we can considerably reduce the loss of life and property.
All natural disasters leave behind a trail of damage, death and destruction, the common problems faced in areas affected by disasters are : 1. A great loss of animal, plant and human life. 2. People get hurt by or buried under fallen debris.
The latex obtained from rubber trees is a suspension of small rubber globules in water and has the appearance of milk. Rubber is obtained by coagulation of the latex by adding dilute acid.