Preparation tricks for GRE are described here: GRE Quant Prep Advice Start with Math concepts books like Manhattan/Kaplan or Magoosh books. These concepts books will give you good foundations of math topics, formula, and how concepts are tested.   Then move to ETS Official GRE books to get the feeling of …

The primary aim of culture preservation is to maintain the organism alive, uncontaminated, and without variation or mutation, that is, to preserve the culture in a condition that is as close as possible to the original isolate. Once a microorganism has been isolated and grown in pure culture, it becomes …

The term ‘ecosystem’ was first used by A. G. Tansley in 1935. Tansley defined an ecosystem as a particular category of physical systems, consisting of organisms and inorganic components in a relatively stable equilibrium, open, and of various sizes and kinds. An ecosystem is a structural and functional unit of …