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

Nutrition in animals  Holozoic nutrition: It is a method of nutrition that involves the ingestion of liquid or solid organic material. It involves different steps namely, ingestion, digestion, absorption, assimilation and egestion. Human beings exhibit holozoic mode of nutrition involving five basic steps. Digestion: Digestion is the process by which complex food is broken down into simple absorbable form. Digestion of food starts from mouth and ends in small intestine Digestive system is made up of alimentary canal and associated glands. Digestive system in human beings: Digestive system in human beings is formed by alimentary canal and digestive glands. Parts of alimentary canal: It comprises different parts like mouth, oesophagus, stomach, small intestine and large intestine. It starts with mouth and ends with anus.  ingestion   The process of taking in food through mouth is called as ingestion. Mastication Teeth help in the process of mastication. Mastication is the proc

Wind Storm and Cyclone :Natural Phenomena: 7th class Hots Questions Question: 1. Why are people advised not to stand near fast moving train? Ans: When train moves with high speed it creates region of lower pressure . This low pressure push man towards the train Question: 2. Why are holes made in huge hoardings? Explain their usefulness. Ans: Holes are made in huge hoardings to reduce air pressurecausing it to flutter or blown away. Question: 3. in winter regions near, why does wind blow from land to sea? Ans:. In winter the sea become warmer quickly than the land. So In winter monsoon blows from land to sea Question: 4. Why are things colorful in appearance? Ans: The colour of object is colour that is reflected. Thus different coulor makes things colourfull. Question: 5. Fill the missing word in the blank spaces in the following statements: (a) Wind is moving air. (b) Winds are generated due to uneven heating on the earth. (c) Near the earth’s surface warm ai

Question: What do you understand by animal nutrition? Answer : Animal nutrition includes requirement of nutrients, mode of intake of food, and its utilization in the body. Question:  What are the main steps of digestion in humans? Answer :  The main steps of digestion in humans are --- (1)  Ingestion (2)  Digestion (3)  Absorption (4)  Assimilation (5)  Egestion Question: What is digestion? Answer :  The breakdown of complex components of food such as carbohydrates into simpler substances is called digestion Question: Name the process of taking in food? Answer :  Ingestion. Question: What are the different modes of taking food into the body in different organisms. Answer : Bees and humming-birds suck the nectar of plants Bees and   humming-birds suck the nectar of plants Snakes like the python swallow the animals they prey upon. Some aquatic animals filter tiny food particles floating nearby and feed upon them. Question: What are