Man does not live by food alone. Water is vital to human health and fitness. Although it is not a nutrient but is as essential as carbohydrates, fats, vitamins and minerals and no life is possible without it. Whereas we can do for weeks without food, we cannot live without water longer than a couple of days. Water approximates 60% of the body weight of the human adults. The total amount of water in a man weighing 70 kilograms is approximately a little over 40 litres. It is an excellent solvent- more substances are soluble in water than in any other liquid known so far. This makes it an ideal constituent of the body fluids which sustain life supporting chemical reactions. It dissolves varied products of digestion and transports them to the rest of the body. Likewise, it dissolves diverse metabolic wastes and helps drain them out of the body. Besides, it performs a variety of functions- some well known and well understood while others not so well appreciated yet vital. The no less important role of water is to distribute/dissipate the body heat efficiently, thereby regulating body’s temperature. Water accomplishes this role ideally because it has high thermal conductivity ensuring rapid heat transfer from one part to the other. Above all, water has a high specific heat, implying that it takes a lot of heat to raise the temperature of water and likewise much heat must be lost to lower its temperature. Answer the following questions briefly: (a) Why is water vital to human health and fitness? (b) Which word in the passage means ‘quick’? (c) How water is an ideal constituent of the body fluids? (d) ‘Water has a high specific heat’. What does it imply? SECTION B: WRITING ( 10 MARKS) 3. You have noted a disturbing trend among children. They spend more time playing video games than in outdoor games or doing physical exercises. Write an Email to your younger brother, highlighting ‘Impact of lesser Physical Activities on Growing Children’ 1X4=4 OR
Answers
a) Water is vital to human health because survival without water is not possible longer than 2-3 days. Also 60% of our body weight is made up of water, implying its significance. Additionally, it is an important part of body fluids, responsible for carrying out many functions.
b) The word "rapid" means quick. It also means in a short time.
c) Water has excellent solvent properties. It is able to dissolve numerous substances and help in the process of transporting products from one part of the body to another. This can mean moving nutrients to different body parts and also moving waste products out of the body.
d) This means that a high amount of heat is involved in raising or lowering the temperature of heat. A lot of heat is needed to raise its temperature. A lot of heat is released when the temperature of water is decreased.
Answer:
(a) Why is water vital to human health and fitness?