long vowel activities

The fan driven by an electric motor reduces the pressure near the mouthpiece. The pressure due to atmosphere being large, forces air along with dust particles into the long tube and then, into the bag. The fan forces the air out of the sweepe..

Active Immunity - Active immunity develops as a result of the contact of an individual with pathogenic organisms or their products. They stimulate the body to produce antibodies in response to the antigens. The immunity thus produced is specific for a particular disease. For e.g..

Different metals get ionised at different rates. For e.g., metals like sodium when exposed to air combine almost instantly with the oxygen present therein (sodium atom gives up an electron almost as soon as it is in contact with oxygen). On the other hand, metals like gold if exposed to air even fo..

Continuous addition of fertilizers without any regard to its dosage, balance between nutrients and requirement of crops has caused loss of fertility - although fertilizers are supplied to improve the nutrient status of soil. Soil has been rendered by modern method of fertilizer usage as a mere phy..

Clonal Selection - B and T lymphocytes have specific receptors on their surface. In B cells, this receptor is the antibody produced by that cell. When this receptor interacts with the antigenic determinant specific to it, the B lymphocyte becomes activated and divides to form a clone of c..

The substances/species produced either by a natural source or by human activity, which cause an adverse effect on the environment on being in excess of a desirable limit, are termed as pollutants. Some common examples of pollutants are carbon monoxide, sulphur dioxide, oxides of nitrogen,..

Adaptations are favourable, heritable variations or changes that enable an organism to increase its chances of survival. Such variations are the result of genetic recombinations or mutations. Adaptations can be either permanent (i.e., heritable from generation to generation) or temporary (i..

They are meant to protect and conserve particular species of wildlife. They are not bound by state legislation. Killing, hunting or capturing of any animal species is prohibited. Forestry and other activities such as grazing of domestic animals are permitted as long as these ac..

Water pollution can be point source or non - point source. That is, it can be caused near the source of pollution or where source of pollution is sometimes far away from source. Nature also contributes to water pollution besides human activities. The concentration of pollutants is..

Air Pollution - Air is an important natural resource providing the basis of life on earth. Entire biosphere depends on air. Air in the atmosphere provides oxygen to plants and animals, by virtue of which they are able to live. The composition of air (78% N, 21% O, 0.03% CO 2 ) is necessary to be ma..