CBSE Class 10th Solutions Maths, Science

  Total coliform counts give a general indication of the sanitary condition of a water supply. Total coliforms  include bacteria that are found in the soil, in water that has been influenced by surface water, and in human or animal waste. Fecal coliforms  are the group of the total coliforms that are considered to be present specifically in the gut and feces of warm-blooded animals. Because the origins of fecal coliforms are more specific than the origins of the more general total coliform group of bacteria, fecal coliforms are considered a more accurate indication of animal or human waste than the total coliforms. Escherichia coli (E. coli)  is the major species in the fecal coliform group. Of the five general groups of bacteria that comprise the total coliforms, only E. coli is generally not found growing and reproducing in the environment. Consequently, E. coli is considered to be the species of coliform bacteria that is the best indicator of fecal pollution and t...

  1. What are trophic levels? Give an example of a food chain and state the different trophic levels in it. Answer: In food chain, the transfer food or energy takes place at the various levels and these levels are known as trophic levels. Example: Grass → Goat → Man In food chain, Grass represents the first trophic level Goat represents the second trophic level Man represents the third trophic level 2. What is the role of decomposers in the ecosystem? Answer: Following is the role of a decomposer in the ecosystem: They act as a cleansing agents of the environment by decomposing the dead plants and animals They help in recycling the nutrients They provide space for new being in the biosphere by decomposing the dead They help in putting back the various elements into water, soil and air for the reuse of producers like crop plants. Activity 15.6 Ozone layer Depletion (Hole in Ozone Layer) Ozone layer recovery research by NASA Activity 15.7 Waste Ma...

 Green house Effect Activity 14.1 􀂄 List four forms of energy that you use from morning, when you wake up, till you reach the school. 􀂄 From where do we get these different forms of energy? 􀂄 Can we call these ‘sources’ of energy? Why or why not? walk by the foot using muscular energy. The food we prepare uses the chemical energy of the liquified petroleum gas (LPG). During our day to day activity, we use electrical energy to run our fans, geysers, air conditioners, etc. Some of our gadgets like calculator, solar lamp, toys run use the energy of sunlight to charge the batteries. Muscular energy in our body comes from the chemical breakdown of carbohydrates and glucose from the cells. LPG comes in the cylinder from a gas supplier which they procure during extraction of fossil fuels. We get electrical energy from various sources. A thermal power plant uses coal to produce electricity; a hydroelectric power plant uses the potential energy of water. Similarly, a solar p...