active involvement in world affairs is called

. Blue green algae (cyanobacteria) represent another major group of prokaryotes. Cyanobacteria are characterised by the presence of phycocyanin (blue) and chlorophyll (green) pigments. The Kingdom Protista includes primitive unicellular eukaryotic organisms. Protista are mainly represented by unice..

For a reaction to occur, reactant molecules must collide with each other. Only those collisions result in product formation which have energy equal or more than a certain minimum energy. This energy is called the threshold energy. This implies that there is an energy barrier between react..

House Keeping Genes - All the genes do not play the same role, nor are all the genes active all the time. With regard to their role and activity, the genes are of two different types- Those genes are constantly transcribed and expressed in the cells because the products they cod..

These are protozoans which occur as endoparasites in different groups of animals. They lack locomotor structures. The body has a tough covering called cuticle and a single nucleus. Asexual reproduction occurs by multiple fission. Sexual reproduction involves anisogamy. Life cycl..

It is a group consisting of multicellular aquatic algae which exhibit a highly varied organisation of the plant body. They are generally found attached to rocky stones. Some of them occur as total or semi parasites on the other algal plants. The members of this group are commonly called ..

Scientific Methodology - Science is basically a collection of knowledge and information that is obtained by observation and testing of natural world, in a logical and orderly manner, and its interpretation. Hence, the basis of science is its orderly, step-wise procedure called s..

>The proteins present in the membrane may function as carriers or receptors or enzymes. Transport across membranes involves several mechanisms. There are processes like diffusion and osmosis, which do not require energy or activity of the cell. Diffusion involves movem..

which have a flat, expanded, leaf like thallus with rootlike rhizoids. E.g., Physcia, Gyrophora. fig. 8.23 - Types of Lichens Fruticose Lichens which have a thallus that is branched and bushy. It may be erect or pendant. Eg: Asnia, Evenia. Lichens reproduce both asexually and sexually. Asex..

A chemical or other environmental agent that produces cancer is called a carcinogen. The world Health organisation estimates that carcinogens may be associated with 60 - 90% of all human cancer. Depending upon their mode of action carcinogens are of 3 types. (1) Carcinogens that..

These are a group of peculiar organisms which share characteristics of fungi and animals. Hence, they are also called as Mycetozoa . In the modern classification they are described as protistan fungi . Most examples of slime moulds are terrestrial and occur in cool, moist and shady places..