List of top Questions asked in CBSE CLASS XII

The objective of Border Roads Organisation is:

Two statements are given below. They are Assertion (A) and Reason (R). Read both the statements carefully and choose the correct option.
% Assertion Assertion (A): The significance of Kolkata sea port has declined in recent times.
% Reason Reason (R): Kolkata port is confronted with the problem of silt accumulation in the Hugli river.

Which one of the following is not a challenge of adolescent population faced by the society?

Identify the characteristics of ‘Phase-I’ of population growth in India and choose the correct option.
I. Stagnant phase of population growth
II. Low or negative net growth of population
III. Rapid fall in the mortality rate
IV. Poor health and medical services

"A very large proportion of workers are engaged in other services in highly urbanized areas." With reference to the given statement choose the correct option.
I. Large scale urbanisation and industrialisation require more workers.
II. Historically, it is a sectoral shift in the economy of the country.
III. Percentage of female workers is relatively high in secondary sector.
IV. It is a shift of workers from farm-based to non-farm-based occupations.

Read the following statements related to ‘intensive subsistence agriculture’ other than paddy in the world carefully and choose the correct option.
I. Wheat is grown in western parts of the Indo-Gangetic plains in India.
II. Wheat is grown in monsoonal areas only.
III. Millets are grown in dry parts of western and southern India.
IV. Wheat, soybean etc. are grown in northern China.

Identify the correct option related to transport services from the following.

Arrange the following sea ports from Europe to India before the operation of Suez Canal and choose the correct option.
I. Cape Town
II. Mombasa
III. London
IV. Mumbai

Choose the correctly matched pair of sea ports and their examples.

Choose the correct option of group of states of iron ore reserves from high to low.

Two statements are given below. They are Assertion (A) and Reason (R). Read both the statements carefully and choose the correct option.
Assertion (A): Foot loose industries can be located in a wide variety of places.
Reason (R): Location of foot loose industries is determined by transport network accessibility.

The basic scheme of the essential steps involved in the process of recombinant DNA technology is summarised below in the form of a flow diagram. Study the given flow diagram and answer the questions that follow: \begin{center} Step-1 \quad Plasmid DNA (cut using Restriction Enzyme EcoR I) \quad + \quad Foreign DNA (cut using Restriction Enzyme EcoR I)
$\downarrow$
DNA ligase
$\downarrow$
Step-2 \quad Recombinant DNA molecule
$\downarrow$
Step-3 \quad Transfer of recombinant DNA molecule to the host cell
$\downarrow$
Step-4 \quad Replication of recombinant DNA molecule in the host cell \end{center} (a) Name the specific enzyme that might have been used to make the multiple copies of foreign DNA before undergoing Step-1 of the process.
(b) How does the use of restriction enzyme EcoR I in Step-1 facilitate the action of DNA ligase to form the recombinant DNA molecule? Explain.
(c) Name the most commonly used host in the above process.