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?
(a) Biodiversity may be defined as the variety of different life forms like plants, animals and microorganisms in an area. Both plants and animals are dependent on each other for the survival. They help each other by the exchange of gases. It means if we remove the one, then it will affect the survival of other organisms or species. To maintain a balance in nature we conserve biodiversity.
(b) Protected forests are also not completely safe for wild animals because as we know forests are the source of food and shelter. So, the people who live near the forests or who lives in the forests uses resources of forests to fulfil their own requirements. People get food, wood and many other things from the forests. People cut wood and kill animals and sell them for money.
(c) Some tribals depend on the jungle as they get food, shelter, fodder and fallen leaves from the jungle. These are their daily needs. So, the tribals depend on forests for their daily needs and for their survival too.
(d) Deforestation is the removal of trees.
Causes of deforestation are as follows:
Consequences of deforestation are as follows:
Describe with the help of a diagram an instrument which can be used to detect a charged body.
Sketch larynx and explain its function in your own words.
Arrange the following boxes in proper order to make a flow chart of sugarcane crop production.
Make a labelled diagram of a candle flame.
What is metamorphosis? Give examples.
The following Table shows the total power shortage in India from 1991– 1997. Show the data in the form of a graph. Plot shortage percentage for the years on the Y-axis and the year on the X-axis.
Make sketches of animal and plant cells. State three differences between them.
What is a constellation? Name any two constellations.
Describe the construction of a kaleidoscope.
Complete the crossword with the help of clues given below:
Across
1. This is necessary for photosynthesis.
3. Term for component present in the cytoplasm.
6. The living substance in the cell.
8. Units of inheritance present on the chromosomes.
Down
1. Green plastids.
2. Formed by collection of tissues.
4. It separates the contents of the cell from the surrounding medium.
5. Empty structure in the cytoplasm.
7. A group of cells.
Give the full form of IVF.
Should the handle and bristles of a tooth brush be made of the same material? Explain your answer.
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.
Complete the cross-word puzzle using the hints given below
Across
1. The process of the fusion of the gametes.
6. The type of fertilization in hen.
7. The term used for bulges observed on the sides of the body of Hydra.
8. Eggs are produced here.
Down
2. Sperms are produced in these male reproductive organs.
3. Another term for the fertilized egg.
4. These animals lay eggs.
5. A type of fission in amoeba.
Fill in the blanks in the following statements:
(a) To draw water from a well we have to ——— at the rope.
(b) A charged body ———— an uncharged body towards it.
(c) To move a loaded trolley we have to ———— it.
(d) The north pole of a magnet ———— the north pole of another magnet.
Explain why plastic containers are favoured for storing food.
What is a constellation? Name any two constellations.
Explain how fertilisers are different from manure.
Mention against each of the following whether regular or diffused reflection will take place when a beam of light strikes. Justify your answer in each case.
(a) Polished wooden table (b) Chalk powder
(c) Cardboard surface (d) Marble floor with water spread over it
(e) Mirror (f) Piece of paper
Differentiate between internal fertilization and external fertilization.