CBSE ADDA

Q. Viruses are considered as being on the border line between living and non-living organisms,Why? Ans: Viruses is nonliving out side living cells but grows and multiplies inside living cell so,viruses are considered as being on the border line between living and non-living organisms.The study of viruses is called Virology. Questions: What does Sargasso Sea woe its name to? Ans: Sargasso Sea woe its name to Sargassum, a particular sea weeds that grow abundantly in sea. Sailor avoids this sea as their boat stuck in the tangled mass of seaweeds. Questions: What are the difference between the cell of bacteria and the cell of other living body? Ans: The difference between the cell of bacteria and the cell of other living body are (i) Cell wall is not made up of cell wall (ii) Do not have nucleus (iii)Does not have membrane bound organelles Questions: Do red and brown algae have chlorophyll? Ans: Yes, red and brown algae have pigment of colour which cover the colour of ch

Solution of chapter Heat and Temperature Basic science Class 7 A. Answer these question in not more than 20 words 1. Give an example to show that heat is a form of energy? Answer: When we heat a pan of water, the water boils and at its temperature rises. The energy for this rise in temperature comes from heat. This shows that heat is a form of energy. 2. What is temperature? Name the scale used to measure it? Answer: Temperature of a body is the measure of the hotness or coldness of the body. Celsius and Fahrenheit are the scales used to measure temperature. Thermometry is branch of physics which deals with the measurement of temperature. 3. If hotness and coldness of a body is relative, how do we measure its degree of hotness? Answer: We measure the degree of hotness or coldness of a body by measuring its temperature and comparing with standard temperature scale. 4. Mention three things that heat causes in substance? Answer: Following are the three changes that hea

High order thinking skill [HOTS Questions] Learnwell science class 8 1. Why are women advised not to wear high heeled shoes? Ans: High heeled shoes do not distribute weight of body over the surface of and therefore women may fall on the ground due to less grips on ground. This is why women are advised not to wear high heeled shoes. 2. It is more difficult to pull boat on the beach than on the water? Ans: Liquid and gases exert lesser friction as compared to solid surfaces. Therefore, boat on the beach experience more friction than on the water. Thus, it is more difficult to pull boat on the beach than on the water. 3. How are you able to drink juice using a straw? Ans: When we suck air from straw the air pressure in the straw decreases that is enough to pull the juice. Air pressure pull the juice to move up inside the straw into our mouth . 4. Why is the tip of sewing needle sharp? Ans: The sharp tip of sewing needle sharp distributes force over less are so tha

Matter in our surrounding solved questions Q. 1. What is a matter? Answer: Anything that occupies space and has mass is called a matter.  For example:- Chalk, Milk, Sugar etc. Q. 2. Sodium chloride and sugar have same appearance. Are they same or different? Answer:  They have different physical and chemical properties. So, they are different Q. 3. All substances around us are alike. How? Answer:  All substances can occupy space and have weight. Q. 4. How can we say that air is a matter? Answer:  Air occupies space and have weight. Hence air is a matter. Q. 5. State the characteristics of matter? Matter has mass, weight and occupies space. Q. 6. What are the intensive properties of matter? Answer:  Density, colour, melting point, boiling point, refractive index etc. are the intensive properties of  matter as it does not depend upon the amount of matter contained in it Q. 7. What are the extensive properties of matter? Answer:  The properti