Indicate whether the following statements are True (T) or False (F):
(a) Oviparous animals give birth to young ones. ( )
(b) Each sperm is a single cell. ( )
(c) External fertilization takes place in frog. ( )
(d) A new human individual develops from a cell called gamete. ( )
(e) Egg laid after fertilization is made up of a single cell. ( )
(f) Amoeba reproduces by budding. ( )
(g) Fertilization is necessary even in asexual reproduction. ( )
(h) Binary fission is a method of asexual reproduction. ( )
(i) A zygote is formed as a result of fertilization. ( )
(j) An embryo is made up of a single cell. ( )
(a) False
This statement is false because oviparous animals lay eggs and viviparous animals give birth to young ones.
(b) True
This statement is true because each sperm is a single cell and an egg is also a single cell.
(c) True
External fertilization takes place outside the female body; they lay eggs and then eggs got hatch and young ones are produced. So, this statement is true that external fertilization takes place in frogs.
(d) False
This statement is false because a new human individual develops not from a cell called gamete. A new individual is formed due to the fusion of two single cells i.e. sperm and egg.
(e) True
Yes, this statement is true because egg is a single cell.
(f) False
This statement is false because amoeba reproduce by binary fission. It is a type of asexual reproduction.
(g) False
This statement is false because fertilization only occurs in sexual reproduction, not in asexual reproduction.
(h) True
This statement is true because asexual reproduction is that in which only single parent is involved. Binary fission, budding are the types of asexual reproduction.
(i) True
Fusion of male and female gamete occurs and forms an zygote. This process of fusion is known as fertilization.
(j) False
This statement is false because embryo is formed by the repeated divisions of zygote or we can say that embryo is the mature zygote.
What is metamorphosis? Give examples.
Define asexual reproduction. Describe two methods of asexual reproduction in animals.
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.
How are test tube babies born?
How are babies produced through IVF technique? What are such babies called?
Differentiate between internal fertilization and external fertilization.
Describe the process of fertilization in human beings.
Give two difference between a zygote and a foetus.
In which female reproductive organ does the embryo get embedded?
How is an embryo developed?
Which of the following can be beaten into thin sheets?
(a) Zinc (b) Phosphorus (c) Sulphur (d) Oxygen
Fill in the blanks
(a) Most liquids that conduct electricity are solutions of , ______________ and ______________.
(b) The passage of an electric current through a solution causes ______________ effects.
(c) If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the terminal of the battery.
(d) The process of depositing a layer ofany desired metal on another material by means of electricity is called .
Give two examples each of situations in which you push or pull to change the state of motion of objects.
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.
List conditions under which combustion can take place.
Indicate whether the following statements are True (T) or False (F).
(a) Unicellular organisms have one-celled body. (T/F)
(b) Muscle cells are branched. (T/F)
(c) The basic living unit of an organism is an organ. (T/F)
(d) Amoeba has irregular shape. (T/F)
Which of the following cannot be charged easily by friction?
(a) A plastic scale
(b) A copper rod
(c) An inflated balloon
(d) A woollen cloth.
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.
Suppose you are in a dark room. Can you see objects in the room? Can you see objects outside the room. Explain.
What are the different ways in which water gets contaminated ?
Explain why some fibres are called synthetic.
Give examples to show that plastics are noncorrosive in nature.
(a) Find out the position of the image of an object situated at A in the plane mirror (Fig. 16.21).
(b) Can Paheli at B see this image?
(c) Can Boojho at C see this image?
(d) When Paheli moves from B to C, where does the image of A move?
Boojho made the following sketch (Fig. 17.29) of the solar system. Is the sketch correct? If not, correct it.
Boojho stands at A just on the side of a plane mirror as shown in Fig. 16.20. Can he see himself in the mirror? Also can he see the image of objects situated at P, Q and R?
The radius of Jupiter is 11 times the radius of the Earth. Calculate the ratio of the volumes of Jupiter and the Earth. How many Earths can Jupiter accomodate?
Two mirrors meet at right angles. A ray of light is incident on one at an angle of 30° as shown in Fig. 16.19. Draw the reflected ray from the second mirror.
Why is the distance between stars expressed in light years? What do you understand by the statement that a star is eight light years away from the Earth?
How many images of a candle will be formed if it is placed between two parallel plane mirrors separated by 40 cm?
What is the angle of incidence of a ray if the reflected ray is at an angle of 90° to the incident ray?