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 bicarbonate (ii) Streptomycin (iii) Alcohol (iv) Yeast
(c) Carrier of malaria-causing protozoan is
(i) female Anopheles mosquito (ii) cockroach (iii) housefly (iv) butterfly
(d) The most common carrier of communicable diseases is
(i) ant (ii) housefly (iii) dragonfly (iv) spider
(e) The bread or idli dough rises because of
(i) heat (ii) grinding (iii) growth of yeast cells (iv) kneading
(f) The process of conversion of sugar into alcohol is called
(i) nitrogen fixation (ii) moulding (iii) fermentation (iv) infection
(a) (ii) Alcohol
Yeast is used in the production of alcohol. This process is known as fermentation.
(b) (ii) Streptomycin
Streptomycin is an antibiotic, it is used to relieve the pain and kills other disease causing microorganisms.
(c) (i) Female Anopheles mosquito
Malaria is caused by a mosquito. The carrier of Malaria causing protozoan is Female Anopheles mosquito.
(d) (ii) Housefly
The most common carrier of communicable disease is housefly. It spreads the disease causing microorganisms.
(e) (iii) Growth of yeast cells
This process is called as fermentation. The dough rises due to the increased growth of yeast cells.
(f) (iii) Fermentation
The conversion of sugar into alcohol with the help of yeast cells is called as fermentation.
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.
What is irrigation? Describe two methods of irrigation which conserve water.
Explain the differences between pure air and polluted air.
Which of the following can be beaten into thin sheets?
(a) Zinc (b) Phosphorus (c) Sulphur (d) Oxygen
Sketch larynx and explain its function in your own words.
Should the handle and bristles of a tooth brush be made of the same material? Explain your answer.
Why should paper be saved? Prepare a list of ways by which you can save paper.
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.
You spill a bucket of soapy water on a marble floor accidently. Would it make it easier or more difficult for you to walk on the floor? Why?
List sources of noise pollution in your surroundings.
Explain why objects moving in fluids must have special shapes.