What is metamorphosis? Give examples.
A change in the animal’s body structure through the cell growth and the differentiation by which an animal develops after birth or hatching is known as metamorphosis. Or, we can say transforming of larva into an adult through a biological process is called as metamorphosis. Metamorphosis involved the sudden and abrupt changes in the structure of an animal. For example: frogs, insects etc.
Life cycle of Frog:
It involves mainly three stages:
Egg → Tadpole → Adult
From the egg tadpole emerges which have gills, tail and a small circular mouth. Tadpole can swim in water freely. Now some sudden and abrupt changes occurs in the structure of tadpole and it develops into a mature frog. The process of metamorphosis starts with the development and finally tail appearance occurs by the body.
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.
Make a labelled diagram of a candle flame.
Arrange the following boxes in proper order to make a flow chart of sugarcane crop production.
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.
Make a sketch of the human nerve cell. What function do nerve cells perform?
Draw a labeled sketch of the human eye.
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.
Four children were asked to arrange forces due to rolling, static and sliding frictions in a decreasing order. Their arrangements are given below. Choose the correct arrangement.
(a) Rolling, static, sliding
(b) Rolling, sliding, static
(c) Static, sliding, rolling
(d) Sliding, static, rolling
Make a sketch of the human nerve cell. What function do nerve cells perform?
Suppose your writing desk is tilted a little. A book kept on it starts sliding down. Show the direction of frictional force acting on it.
Word game : Use the clues to work out the words.
Across
3. Protruding voice box in boys
4. Glands without ducts
7. Endocrine gland attached to brain
8. Secretion of endocrine glands
9. Pancreatic hormone
10. Female hormone
Down
1. Male hormone
2. Secretes thyroxine
3. Another term for teenage
5. Hormone reaches here through blood stream
6. Voice box
7. Term for changes at adolescence
Make a labelled diagram of a candle flame.
Which zone of a flame does a goldsmith use for melting gold and silver and why?
The process that you saw in Activity 14.7 is used for purification of copper. A thin plate of pure copper and a thick rod of impure copper are used as electrodes. Copper from impure rod is sought to be transfered to the thin copper plate. Which electrode should be attached to the positive terminal of battery and why?
Iqbal has to push a lighter box and Seema has to push a similar heavier box on the same floor. Who will have to apply a larger force and why?
It is difficult to burn a heap of green leaves but dry leaves catch fire easily. Explain.