What will happen if:
(a) we go on cutting trees.
(b) the habitat of an animal is disturbed.
(c) the top layer of soil is exposed.
(a) If we go on cutting trees: If we go no cutting trees then the habitat of the wild animals will be destroyed completely. The level of the carbon dioxide increases which may leads to the global warming. So, biodiversity is extremely affected by the deforestation which may lead to the danger of the survival of the many organisms.
(b) If the habitat of an animal is disturbed: A habitat is a place where an organism lives. It provides shelter, food and many other important things which are necessary for the survival. If the habitat of an animal is disturbed then they all have to move from that place to another for food and shelter. During this process, animal may get killed by the others.
(c) If the top layer of the soil is exposed: The upper/ top layer of the soil is fertile and the inner layer of the soil is rocky and hard. If the top layer of the soil is exposed, then the lower layer of the soil is exposed which is infertile.
The upper layer of the soil has humus whereas the lower layer does not have humus. If the continued exposure of the top layer of the soil occurs, it may lead to the soil erosion. It will make the land fertile.
Discuss the effects of deforestation on the following:
(a) Wild animals
(b) Environment
(c) Villages (Rural areas)
(d) Cities (Urban areas)
(e) Earth
(f) The next generation
Answer in brief:
(a) Why should we conserve biodiversity?
(b) Protected forests are also not completely safe for wild animals. Why?
(c) Some tribals depend on the jungle. How?
(d) What are the causes and consequences of deforestation?
(e) What is Red Data Book?
(f) What do you understand by the term migration?
Find out the information about the national parks in your state. Identify and show their location on the outline map of India.
Complete the word puzzle:
Down
1. Species on the verge of extinction.
2. A book carrying information about endangered species.
5. Consequence of deforestation.
Across
1. Species which have vanished.
3. Species found only in a particular habitat.
4. Variety of plants, animals and microorganisms found in an area.
Differentiate between the following:
(a) Wildlife sanctuary and biosphere reserve
(b) Zoo and wildlife sanctuary
(c) Endangered and extinct species
(d) Flora and fauna
Why should paper be saved? Prepare a list of ways by which you can save paper.
In order to meet the ever-increasing demand in factories and for shelter, trees are being continually cut. Is it justified to cut trees for such projects? Discuss and prepare a brief report.
Explain how deforestation leads to reduced rainfall.
How can you contribute to the maintenance of green wealth of your locality? Make a list of actions to be taken by you.
Fill in the blanks:
(a) A place where animals are protected in their natural habitat is called .
(b) Species found only in a particular area is known as .
(c) Migratory birds fly to far away places because of changes.
Which of the following can be beaten into thin sheets?
(a) Zinc (b) Phosphorus (c) Sulphur (d) Oxygen
Fill in the blanks
(a) Most liquids that conduct electricity are solutions of , ______________ and ______________.
(b) The passage of an electric current through a solution causes ______________ effects.
(c) If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the terminal of the battery.
(d) The process of depositing a layer ofany desired metal on another material by means of electricity is called .
Give two examples each of situations in which you push or pull to change the state of motion of objects.
Fill in the blanks:
(a) Friction opposes the _____________ between the surfaces in contact with each other.
(b) Friction depends on the _____________ of surfaces. (c) Friction produces __________.
(d) Sprinkling of powder on the carrom board ________ friction.
(e) Sliding friction is ___________ than the static friction.
List conditions under which combustion can take place.
Indicate whether the following statements are True (T) or False (F).
(a) Unicellular organisms have one-celled body. (T/F)
(b) Muscle cells are branched. (T/F)
(c) The basic living unit of an organism is an organ. (T/F)
(d) Amoeba has irregular shape. (T/F)
Which of the following cannot be charged easily by friction?
(a) A plastic scale
(b) A copper rod
(c) An inflated balloon
(d) A woollen cloth.
Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room. Explain.
What are the different ways in which water gets contaminated ?
Explain the importance of reproduction in organisms.
Boojho made the following sketch (Fig. 17.29) of the solar system. Is the sketch correct? If not, correct it.
(a) Find out the position of the image of an object situated at A in the plane mirror (Fig. 16.21).
(b) Can Paheli at B see this image?
(c) Can Boojho at C see this image?
(d) When Paheli moves from B to C, where does the image of A move?
The radius of Jupiter is 11 times the radius of the Earth. Calculate the ratio of the volumes of Jupiter and the Earth. How many Earths can Jupiter accomodate?
Boojho stands at A just on the side of a plane mirror as shown in Fig. 16.20. Can he see himself in the mirror? Also can he see the image of objects situated at P, Q and R?
Why is the distance between stars expressed in light years? What do you understand by the statement that a star is eight light years away from the Earth?
Two mirrors meet at right angles. A ray of light is incident on one at an angle of 30° as shown in Fig. 16.19. Draw the reflected ray from the second mirror.
Do all the stars in the sky move? Explain.
How many images of a candle will be formed if it is placed between two parallel plane mirrors separated by 40 cm?
Explain how you can locate the Pole Star with the help of Ursa Major.
What is the angle of incidence of a ray if the reflected ray is at an angle of 90° to the incident ray?