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Which of the following is a recently originated problem of environment? (a) Ozone layer depletion (b) Greenhouse effect (c) Global warming (d) All of the above

d) All of these Ozone layer depletion The ozone layer is a region in the earth’s stratosphere that contains high concentrations of ozone... View Article

Increased concentration of nitrogen in the air is believed to cause global warming. (True or False). Also write the false statements in their correct form.

False. An increase in the CO2 in the air is the cause of global warming. There are various causes of global warming, both natural and man made.... View Article

The main function of abscisic acid in plants is to (a) increase the length of cells (b) promote cell division (c) inhibit growth (d) promote the growth of stem

c) Inhibit growth Abscisic acid (ABA) is a plant hormone. ABA capacities in many plant formative cycles, including seed and bud lethargy, the... View Article

A synthetic fibre which looks like silk is obtained by chemical treatment of wood pulp. It is, therefore, known as artificial silk. What is its common name?

Rayon is obtained by the chemical treatment of wood pulp or cellulose. A synthetic fibre that looks like silk is obtained by chemical treatment... View Article

Difference Between Encoder and Decoder

Encoder and Decoder are combinational logic circuits. One of the major differences between these two terminologies is that the encoder gives... View Article

Classify the following crops into Kharif and Rabi crops and write in the tabular column given below: Maize, paddy, mustard, pea, gram, wheat, groundnut, cotton.

Kharif: Maize, paddy, groundnut, cottonRabi : Mustard, pea, wheat, gram The crops that are sown in the rainy season are called kharif crops.... View Article

Two green plants are kept separately in oxygen-free containers, one in the dark and the other in continuous light. Which one will live longer? Give reasons.

The plant which is kept in continuous light will live longer. We know that plant release carbon dioxide during respiration. In case of plant... View Article

Which of the following are Indian cattle? (i) Bos indicus (ii) Bos domestica (iii) Bos bubalis (iv) Bos vulgaris (a) (i) and (iii) (b) (i) and (ii) (c) (ii) and (iii) (d) (iii) and (iv)

a) (i) and (iii) Bos indicus is an Indian cattle and Bos babalis is an Indian cattle but not Bos bubalis.(Bos Taurus Indicus) on the other hand... View Article

Select the articles from the following list which are biodegradable. (a) Paper (b) Woollen clothes (c) Wood (d) Aluminium can (e) Plastic bag (f) Peels of vegetables

The list of biodegradable articles is mentioned below - (a) paper (b) woolen clothes (c) wood (f) peels of vegetables. A biodegradable material... View Article

Which of the following groups contain all synthetic substances? (a) Nylon, Terylene, Wool (b) Cotton, Polycot, Rayon (c) PVC, Polythene, Bakelite (d) Acrylic, Silk, Wool

(c) PVC, Polythene, Bakelite Synthetic materials are made by chemically changing the starting substances to create a material with different... View Article

Given below are statements about the harmful effects of weeds on crop plants. (i) They interfere with harvesting. (ii) They help crop plants to grow healthily. (iii) They compete with crop plants for water, nutrients, space and light. (iv) They affect plant growth. Choose the correct combination of statements. (a) i, iii, iv (b) iii only (c) iii, iv (d) i, ii, iii, iv

(a) i, iii, iv Harmful effects of weeds on crop of plant are as follows: They interfere in harvesting. They compete with crop plants for... View Article

Given below is a conversation between two farmers Heera and Beera. Heera: Brother Beera, your maize crops looks beautiful! They have grown pretty fast. Beera: Yes, I have sprayed urea this time. What about you? Heera: Well, I am still relying on good old cow dung. I am saving money on buying a tractor. Beera: That’s good. Tractor saves a lot of time and labour. Heera: Yes, it’s been very labour intensive for me and now these weeds have come up. Beera: Try weedicides, they are very effective. Now answer the following questions. a) List the practices which are not environment-friendly and why? b) What is the advantage of modern agriculture implements over traditional ones? c) Name one weedicide and the precaution farmers must take during its application.

a) The use of chemical fertilizers, insecticides, pesticides, weedicides are not environment-friendly as they contain chemicals which are very... View Article

The calorific value of a fuel is expressed in a unit called (a) kilojoule per litre (b) kilogram per millilitre (c) kilojoule per gram (d) kilojoule per kilogram

The calorific value of a fuel is expressed in a unit called kilojoule per kilogram. Calorific value is the amount of energy released or produced... View Article

Rohit took with him some nylon ropes when he was going for rock climbing. Can you tell why he selected nylon ropes instead of ropes made of cotton or jute?

Nylon ropes are strong, elastic and lighter as compared to cotton and jute ropes. Nylon is the most useful synthetic material with... View Article

The process of loosening and turning of soil is called (a) irrigation and manuring (c) tilling and ploughing (b) digging and winnowing (d) harvesting and storage

The process of loosening and turning of soil is called Tilling or ploughing. Before sowing the seeds, it is necessary to loosen and turn the soil... View Article

Classify the following diseases as infectious or non-infectious. (a) AIDS (b) Tuberculosis (c) Cholera (d) High blood pressure (e) Heart disease (f) Pneumonia (g) Cancer

(a) AIDS - Infectious (b) Tuberculosis - Infectious (c) Cholera - Infectious (d) High blood pressure – No- Infectious (e) Heart disease... View Article

Observe the figure given and answer the questions that follow. (a) Label A and B. (b) Identify the process. (c) What happens during this process and what is formed?

(a) A-sperm; B-ovum (egg) Sperm and ovum are the gametes produced by vertebrates. More specifically, sperm is the male gamete while the ovum is... View Article

Which of the following statements about reproduction in humans is correct? (a) Fertilisation takes place externally. (b) Fertilisation takes place in the testes. (c) During fertilisation, egg moves towards the sperm. (d) Fertilisation takes place in the human female.

d) Fertilisation takes place in the human female (oviduct). The female reproductive system is framed to perform different functions. It creates... View Article

Why does moon have very cold and very hot temperature variations eg., from -190°C to 110°C even though it is at the same distance from the sun as the earth is?

The moon has no atmosphere, unlike Earth. The energy from the Sun heats up the land as well as the air; hence the temperature does not drop too... View Article

One of the following processes is not a step involved in the water-cycle operating in nature (a) evaporation (b) transpiration (c) precipitation (d) photosynthesis

d) Photosynthesis There are many processes involved in the movement of water. Listed below are different stages of the water cycle. The sun... View Article

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