CBSE Sample Paper 2021 Class 8 Science Half Yearly
Half Yearly Examination (2020-21)
All questions are compulsory.
1- Choose the correct options:- (6)
i) Coal mainly contains :-
ii) Which of these is not a source of energy?
iii) Which of these does not help in starting fire?
iv) Which of the following is not a natural?
v) Male gonads are called –
2- Match the following :-(6)
i) Cell wall Hydra
ii) Nucleus female gametes
iii) Ribosome controls all the activities of the cell.
iv) Egg Amoeba
v) Budding Protein synthesis
vi) Binary fission Protection and shape
3- Fill in the blanks :- (8)
i- The liquid fossil fuel is ____________.
ii- ____________ should never be used in case of an electrical fire.
iii- The animals nearing extinction are called ____________.
iv- Internal fertilization takes place in____________.
v- ____________ are the female gonads of human beings.
vi- ____________ involves the splitting of an organism into two.
vii- ____________ release sperm.
viii- In humans fertilization occur in____________.
4- Write T for the true statement and F for the false statements: -(8)
i- Large – sized vacuoles are present animal’s cells.
ii- The cell membrane is selectively permeable.
iii- Flora means plants and fauna means animals.
iv- Ecosystem is the clearing of forests for agriculture.
v- Centrioles help in cell division in animal cells.
vi- Chromo plasts are found in the green parts of the plants.
vii- Amoeba is a single – Celled animals.
viii- Reforestation could lead to and increases in carbon- dioxide.
5- Give reasons for the following.(8)
i- LPG is a better fuel than wood.
ii- Water should not be used in case of a fire in a petrol tank or an electric fire.
iii- A washer man uses charcoal for ironing clothes.
iv- CNG is a better fuel for automobiles.
6- Answer the following questions in one word :-(8)
i- Name a cooking gas.
ii- What is called a black gold?
iii- The gradual conversion of fertile soil into wasteland.
iv- What is called if trees are cutting on a large scale?
v- Name a type of coal which has the highest carbon content.
vi- The process of extraction of resources from earth.
vii- Name the compounds made from petroleum.
viii- Name a moth repellent made from coal tar.
7- Short answers type questions. (Do any eight) (16)
i- What is the impact of using excess of fossil fuels?
ii- What are the characteristics of an ideal fuel?
iii- Why are biodiversity parks being made in different ports of India?
iv- Why the nuclease is called the control centre of the cell.
v- List the male and female reproductive organs of human body?
vi- What are the functions of vacuoles?
vii- Why are biodiversity parks being made in different park s of India?
viii- Why substances do produces flames of different colors?
ix- Why is conservation of fossil fuels essential?
x- What are gonads and what do they produce?
8- Long answers type questions (Do any four) (16)
i- Which virus causes AIDS? What are the ways in which it can be transmitted?
ii- Explain menstrual cycle and the changes that occur in an adolescent girl during the menstrual cycle?
iii- Life begins from a single cell called zygote Explain the statement.
iv- How does fertilization take place in frogs?
v- What are the cell theory states?
vi- How can citizens help in the conservation of plants and animals?
9- Draw any one lablled diagram of the following :- (4)
i- Life cycle of a frog
ii- A plant cell
iii- A candle flame