Write notes on—
(a) Adam’s apple.
(b) Secondary sexual characters.
(c) Sex determination in the unborn baby.
(a) Adam’s apple:
During the puberty, the larynx grows larger in male in human beings. It can be seen as a protruding part of the throat. This is called as Adam’s apple. Larynx becomes prominent in boys because of sex hormones. Due to which the vocal cords becomes longer and thicker which leads to a hoarse voice. However, the larynx is of small size in females and it is hardly visible. Girls have a high pitched voice because of the smaller size of the larynx.
(b) Secondary sexual characters:
Sex hormones are responsible for secondary sexual characters in males and females. Males and females are distinguished by the sexual characters. At the time of puberty, the secondary sexual characters are the physical and behavioral changes that appears in humans.
Secondary sexual characters that are appears in boys are as follows:
Secondary sexual characters that are appears in females are as follows:
The sex of the baby is determined by the male gamete that fuses with the female gamete.
23 pairs of chromosomes are present in humans. Out of these pair, the last pair is known as the sex chromosomes.
Male have XY sex chromosome and male gamete can be of two types:
22 + X ; 22 + Y
Whereas female has XX chromosomes and type of female gamete:
22 + X
; X is responsible for a baby girl.
Y is responsible for a baby boy.
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.
Sketch larynx and explain its function in your own words.
Explain in what way noise pollution is harmful to humans.
Explain why the sliding friction is less than the static friction.
An archer stretches her bow while taking aim at the target. She then releases the arrow, which begins to move towards the target. Based on this information fill up the gaps in the following statements using the following terms:
muscular, contact, non-contact, gravity, friction, shape, attraction
(a) To stretch the bow, the archer applies a force that causes a change in its ——.
(b) The force applied by the archer to stretch the bow is an example of ——— force.
(c) The type of force responsible for a change in the state of motion of the arrow is an example of a ———— force.
(d) While the arrow moves towards its target, the forces acting on it are due to ———— and that due to ———— of air.
Match items in column A with one or more items in column B:
A B
(i) Inner planets (a) Saturn
(ii) Outer planets (b) Pole Star
(iii) Constellation (c) Great Bear
(iv) Satellite of the Earth (d) Moon
(e) Earth
(f) Orion
(g) Mars
Write a short paragraph on the harms caused by microorganisms.
Rana wants to buy shirts for summer. Should he buy cotton shirts or shirts made from synthetic material? Advise Rana, giving your reason.
Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room. Explain.
Explain how CO2 is able to control fires.
Draw a labeled sketch of the human eye.