Adichotomous key works on the principle of asking yes-or-no questions about the organism. to identify it, the answers for that organism are then compared to existing organisms to identify it. prepare a list of four to five questions about each of the organisms listed below to you create your own key. for each question, make sure the answer isn’t the same for all four organisms. for example, does the organism have cells? would be an inappropriate question, because all the organisms have cells. brewer’s yeast (saccharomyces cerevisiae) e. coli bacteria (escherichia coli) green hydra (hydra viridissima) house cat (felis catus)

affects the water bodies: excessive use of fertilizers causes eutrophication. the fertilizers which are used on plants affect the quality of land on which it is used, further causing erosion of soil. the fertilizers used on plants contain harmful chemical fumes which affect the environment.

the food storage products of chrysophytes are oils or the polysaccharide laminarin.   formerly classified as plants, the chrysophytes contain the photosynthetic pigments chlorophyll a and c all but the yellow-green algae also contain the carotenoid pigment fucoxanthin.

igneous rocks are formed by solidification of cooled magma (molten rock), with or without crystallization, either below the surface as intrusive (plutonic) rocks or on the surface as extrusive (volcanic) rocks.  

the composition depends on the source magma. there are almost a thousand types of composition found till now.  

hope this