What are sex hormones? Why are they named so? State their function.
The chemical substances produced by sex organs are called sex hormones. For example:
Sex hormones affects the sexual features of an organism. So, they named as sex hormones. Sex hormones play a important role in our body. Some of the function of sex hormones are as follows:
Testosterone: It is the male sex hormone. It is responsible for secondary sexual characters in male body like growth of beard, developing of reproductive organs and the voice becomes hoarse etc.
Oestrogen: It is the female sex hormone. It is responsible for the secondary sexual characters in the female body like increase in the size of breast, voice becomes soft, development of reproductive organs etc.
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.
Explain why the sliding friction is less than the static friction.
Explain the difference between the thermoplastic and thermosetting plastics.
You are a member of the municipal body of your town.
Make a list of measures that would help your town to ensure the supply of clean water to all its residents.
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.
Identify the part which vibrates to produce sound in the following instruments:
(a) Dholak (b) Sitar (c) Flute
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.
Give examples to show that friction is both a friend and a foe.
List changes in the body that take place at puberty.
Name the forces acting on a plastic bucket containing water held above ground level in your hand. Discuss why the forces acting on the bucket do not bring a change in its state of motion.
At an individual level, how can you help reduce air pollution?