Compare the above system with the probable systems in hilly/mountainous areas or plains or plateau regions.
In the plain regions, the water harvesting systems possess crescent- shaped earthen embankments, low, straight or concrete. Monsoon rain filled behind the structures only the large structure will hold the water for the long- range; or in hilly or mountainous regions canal irrigation system also called Kuls (water channels filled during the rain and carries it to various locations, i.e diverted into the man- made channels down the hillsides cause in the hilly area only terrace farming occurs, so there is no plain area) and ponds are used for the water harvesting or management; or in the plateau regions Cheruvu is used to store the runoff water.
Find out about the traditional systems of water harvesting/management in your region.
Suggest some approaches towards the conservation of forests.
We saw in this chapter that there are four main stakeholders when it comes to forests and wildlife. Which among these should have the authority to decide the management of forest produce? Why do you think so?
List five things you have done over the last one week to —
(a) conserve our natural resources.
(b) increase the pressure on our natural resources.
Find out the source of water in your region/locality. Is water from this source available to all people living in that area?
How can you as an individual contribute or make a difference to the management of (a) forests and wildlife, (b) water resources and (c) coal and petroleum?
Why should we conserve forests and wildlife?
What changes can you make in your habits to become more environment-friendly?
What can you as an individual do to reduce your consumption of the various natural resources?
Why do you think that there should be equitable distribution of resources? What forces would be working against an equitable distribution of our resources?
Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.
What is a good source of energy?
Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?
What are trophic levels? Give an example of a food chain and state the different trophic levels in it.
What is the difference between a reflex action and walking?
What is the importance of DNA copying in reproduction?
If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?
Why should a magnesium ribbon be cleared before burning in air?
Define the principal focus of a concave mirror.
You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?
A student has difficulty reading the blackboard while sitting in the last row. What could be the defect the child is suffering from? How can it be corrected?
Translate the following statements into chemical equations and then balance them.
(a) Hydrogen gas combines with nitrogen to form ammonia.
(b) Hydrogen sulphide gas burns in air to give water and sulpur dioxide.
(c) Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
(d) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas.
Which gas is produced when dilute hydrochloric acid is added to a reactive metal? Write the chemical reaction when iron reacts with dilute H2SO4.
Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?
An object is placed at a distance of 10 cm from a convex mirror of focal length 15 cm. Find the position and nature of the image.
How is the concentration of hydroxide ions (OH-) affected when excess base is dissolved in a solution of sodium hydroxide?
Which of the following property of a proton can change while it moves freely in a magnetic field? (There may be more than one correct answer.)
(a) mass (b) speed
(c) velocity (d) momentum
Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.
Why is respiration considered an exothermic reaction? Explain.
Explain the following in terms of gain or loss of oxygen with two examples each.
(a) Oxidation
(b) Reduction