Question 1: What are the various constituents of domestic sewage? Discuss the effects of sewage discharge on a river. Answer: Domestic sewage is the waste originating from the kitchen, toilet, laundry, and other sources. It contains impurities such as suspended solid (sand, salt, clay), colloidal material (fecal matter, bacteria, plastic and cloth fiber), dissolved materials … Read more
Question 1: Name the three important components of biodiversity. Answer: Biodiversity is the variety of living forms present in various ecosystems. It includes variability among life forms from all sources including land, air, and water. Three important components of biodiversity are: (a) Genetic diversity (b) Species diversity (c) Ecosystem diversity Question 2: How do ecologists … Read more
Question 1: Fill in the blanks. (a) Plants are called as_________ because they fix carbon dioxide. (b) In an ecosystem dominated by trees, the pyramid (of numbers) is _________ type. (c) In aquatic ecosystems, the limiting factor for the productivity is _________. (d) Common detritivores in our ecosystem are_________. (e) The major reservoir of carbon … Read more
Question 1: How is diapause different from hibernation? Answer: Diapause is a stage of suspended development to cope with unfavourable conditions. Many species of Zooplankton and insects exhibit diapause to tide over adverse climatic conditions during their development. Hibernation or winter sleep is a resting stage where in animals escape winters (cold) by hiding themselves … Read more
Question 1: Crystals of Bt toxin produced by some bacteria do not kill the bacteria themselves because − (a) bacteria are resistant to the toxin (b) toxin is immature: (c) toxin is inactive: (d) bacteria encloses toxin in a special sac. Answer: toxin is inactive: In bacteria, the toxin is present in an inactive form, … Read more
Question 1: Bacteria cannot be seen with the naked eyes, but these can be seen with the help of a microscope. If you have to carry a sample from your home to your biology laboratory to demonstrate the presence of microbes under a microscope, which sample would you carry and why? Answer: Curd can be … Read more
Question 1: Explain in brief the role of animal husbandry in human welfare. Answer: Animal husbandry deals with the scientific management of livestock. It includes various aspects such as feeding, breeding, and control diseases to raise the population of animal livestock. Animal husbandry usually includes animals such as cattle, pig, sheep, poultry, and fish which … Read more
Question 1: What are the various public health measures, which you would suggest as safeguard against infectious diseases? Answer: Public health measures are preventive measures which are taken to check the spread of various infectious diseases. These measures should be taken to reduce the contact with infectious agents. Some of these methods are: (1) Maintenance … Read more
Question 1: Explain antibiotic resistance observed in bacteria in light of Darwinian selection theory. Answer: Darwinian selection theory states that individuals with favourable variations are better adapted than individuals with less favourable variation. It means that nature selects the individuals with useful variation as these individuals are better evolved to survive in the existing environment. … Read more
Question 1: Group the following as nitrogenous bases and nucleosides: Adenine, Cytidine, Thymine, Guanosine, Uracil and Cytosine. Answer: Nitrogenous bases present in the list are adenine, thymine, uracil, and cytosine. Nucleosides present in the list are cytidine and guanosine. Question 2: If a double stranded DNA has 20 per cent of cytosine, calculate the per … Read more