List of top Questions asked in CBSE CLASS XII

Bt-toxin genes have been expressed in plants in order to provide resistance against:
• [(i)] lepidopterans and fungi
• [(ii)] animals and bacteria
• [(iii)] coleopterans and dipterans
• [(iv)] lepidopterans
Assertion (A): Repetitive sequences make up a very large portion of human genome.
Reason (R): Repetitive sequences do not have direct coding functions in the genome.
According to IUCN, some of the extinctions include:
• [(i)] Dodo
• [(ii)] Indian gazelle
• [(iii)] Thylacine
• [(iv)] Steller’s Sea Cow
Assertion (A): The endometrium undergoes cyclic changes during the menstrual cycle.
Reason (R): Perimetrium contracts strongly during delivery of the baby.
Assertion (A): Genetically modified microbes help in crop protection.
Reason (R): Bacillus thuringiensis (Bt) bacteria control insects by producing prototoxins.
Select the odd option in the context of convergent evolution.
Which of the following ecosystems is most productive in terms of net primary productivity?
Monascus purpureus is a yeast used commercially in the production of which one of the following?
Given below is the restriction site of a restriction endonuclease Pst I and the cleavage sites on a DNA molecule.
Choose the option that gives the correct resultant fragments.
During different phases of menstrual cycle, hormones are secreted. Choose the option showing the correct sequence of hormones.
S is the stimulant of central nervous system and interferes with the transport of T, a neurotransmitter. Identify S and T and choose the correct option.
Arrange the following in the correct sequence of their evolution and select the correct option:
• [(i)] Seaweed
• [(ii)] Invertebrates
• [(iii)] Jawless fish
The cells of endosperm have 24 chromosomes. What will be the number of chromosomes in the gametes?
A DNA molecule is 160 base pairs long. It has 30% Guanine. How many Adenine bases are present in this DNA molecule?
In a human female, menstrual cycle of 28 days is represented by the diagram given below (Phase I: Days 1--5, Phase II: Days 6--13, Phase III: Days 15--28). Select the correct statement related with this diagram.
Pahari miniature reflects the freedom the artists were given to show diversity of artistic expression within miniature style. Choose one of the paintings given below and answer:
(i) Write the name of the artist and the sub-school of painting.
(ii) Explain any two characteristics of the sub-school.
(a) Krishna with Gopis
OR
(b) Nand, Yashoda and Krishna with kinsmen going to Vrindavan
State any three points of significance of Principles of Management.
A statement which conveys the exact message that you are trying to convey to the other person is called a/an _____________ statement.
At which age does a child have a vocabulary of 2000 to 2500 words?
Hands should be thoroughly washed for _________ to maintain personal hygiene.
How does the disease spread?
Select the composer of Tillana :
A relation $R$ on set $A=\{1,2,3\}$ defined as $R=\{(1,2),(2,1),(2,2)\}$ is
Which of the following encourages development and implementation of open standards for geospatial content and services?
Name any two types of antibodies found to give humoral immune response in humans.