Recent posts
View all
Reproduction In Animals
Exercises 1. Explain the importance of reproduction in organisms. Ans:- Reproduction is essential for the continuation of a species. In other words, reproduction is very important as it ensures the continuation of similar kinds of individuals, generation after generation. 2. Describe the process of fertilisation in human beings. Ans:- The first step in the process of reproduction is the fusion of a sperm and an ovum. When sperms come in contact with an egg, one of the sperms may fuse with the egg. Such fusion of …
Cell - Structure And Functions
Exercises 1. Indicate whether the following statements are True (T) or False (F). (a) Unicellular organisms have one-celled body. (T) (b) Muscle cells are branched. (F) (c) The basic living unit of an organism is an organ. (F) (d) Amoeba has irregular shape. (T) 2. Make a sketch of the human nerve cell. What function do nerve cells perform? Ans:- Function of nerve cell : The nerve cell receives and transfers messages, thereby helping to control and coordinate the working of different parts of the bod…
Conservation of Plants And Animals
Exercises 1. Fill in the blanks. (a) A place where animals are protected in their natural habitat is called wildlife sanctuary . (b) Species found only in a particular area is known as endemic species . (c) Migratory birds fly to far away places because of climatic changes. 2. Differentiate between the following. (a) Wildlife sanctuary and biosphere reserve Ans:- (b) Zoo and wildlife sanctuary Ans:- (c) Endangered and extinct species Ans:- (d) Flora and fauna Ans:- 3. Disc…
Combustion And Flame
Exercises 1. List conditions under which combustion can take place. Ans:- Following are the required for combustion : presence of fuel air to supply Oxygen heat to raise the temperature of the fuel beyond its ignition temperature 2. Fill in the blanks. (a) Burning of wood and coal causes pollution of air. (b) A liquid fuel, used in homes is liquefied petroleum gas(LPG) . (c) Fuel must be heated to its before it ignition temperature starts burning. (d) Fire produced by oil cannot b…
Coal And Petroleum
Exercises 1. What are the advantages of using CNG and LPG as fuels? Ans:- The advantages of CNG and LPG as fuels are: can be transported easily through pipes. cost is low thus cheap fuels. they can burn directly and easily. CNG is used as a transport fuel since it doesn't give toxic fumes. CNG is used for power generation. they are clean fuels as they don't give smoke when burnt. 2. Name the petroleum product used for surfacing of roads. Ans:- Bitumen is a petroleum product used for surfacing of road…
Materials : Metals And Non-Metals
Exercises 1. Which of the following can be beaten into thin sheets? (a) Zinc (b) Phosphorus (c) Sulphur (d) Oxygen 2. Which of the following statements is correct? (a) All metals are ductile. (b) All non-metals are ductile. (c) Generally, metals are ductile. (d) Some non-metals are ductile. Ans:- (c) Generally, metals are ductile. 3. Fill in the blanks. (a) Phosphorus is a very reactive non-metal. (b) Metals are good conductors of heat and …
Synthetic Fibres And Plastics
Exercises 1. Explain why some fibres are called synthetic. Ans:- Fabrics are made from fibres obtained from natural or artificial sources.The fibres which are made by human beings are called synthetic fibres. 2. Mark the correct answer. Rayon is different from synthetic fibres because (a) it has a silk-like appearance. (b) it is obtained from wood pulp. (c) its fibres can also be woven like those of natural fibres. Ans:- (b) it is obtained from wood pulp. 3. Fill in the blanks with appropriate words. (a) Synthetic…
Microorganisms : Friend And Foe
Exercises 1. Fill in the blanks. (a) Microorganisms can be seen with the help of a microscope . (b) Blue green algae fix nitrogen directly from air and enhance fertility of soil. (c) Alcohol is produced with the help of yeasts . (d) Cholera is caused by bacteria . 2. Tick the correct answer. (a) Yeast is used in the production of (i) sugar (ii) alcohol (iii) hydrochloric acid (iv) oxygen (b) The following is an antibiotic (i) Sodium bicarbona…
Crop Production And Management
Exercises 1. Select the correct word from the following list and fill in the blanks. float, water, crop, nutrients, preparation (a) The same kind of plants grown and cultivated on a large scale at a place is called crop . (b) The first step before growing crops is preparation of the soil. (c) Damaged seeds would float on top of water. (d) For growing a crop, sufficient sunlight and water and nutrients from the soil are essential. 2. Match items in column A with th…
Social Plugin