CBSE 12TH BIOLOGY - Online Test
Q1. Wild animals :
i) Frequently breed in Zoos.
ii) Reproductive capacity is lowered if area of free movement is reduced.
i) Frequently breed in Zoos.
ii) Reproductive capacity is lowered if area of free movement is reduced.
Answer : Option D
Explaination / Solution:
Reproductive capacity of an animals is lowered if area of free movement is reduced. So, wild animals do not breed frequently in Zoos. So, statement i is wrong and ii is correct.
Q2. Sertoli cells present in the testis act as
Answer : Option D
Explaination / Solution:
Large pillar like cells in the germinal epithelium of the testis that support and nourish developing spermatozoa are Sertoli cells.
Q3. Which among the following occurs in pair?
Answer : Option B
Explaination / Solution:
Both gene and chromosome occurs in pair and segregate during gamete formation by reduction division or meiosis.
Q4. Which of the following is a gram-negative bacterium?
Answer : Option C
Explaination / Solution:
The bacterium that do not retain the Gram stain are called gram negative bacteria.
Escherichia coli ( commonly abbreviated E. coli) is a Gram-negative gammaproteobacterium commonly found in the lower intestine of warm-blooded organisms
Q5. Using the same land for farming, forestry as well as animal husbandry will be called
Answer : Option A
Explaination / Solution:
Agroforestry is the using of same land for farming, forestry as well as animal husbandry in integrated manner. The byproduct of one process in used in another process.
Q6. E. coli carry resistance to
Answer : Option A
Explaination / Solution:
Bacterium E.coli carries resistance to antibiotic Fluroquitnolone due to presence of plasmid having extra nuclear DNA.
Q7. According to De Vries theory, evolution is
Answer : Option A
Explaination / Solution:
According to De Vries theory of evolution, the evolution is jerky and discontinuous as the variation due to mutation do not occurs continually. Mutation is sudden change in gene of organism.
Q8. Which type of vegetative propagation is present in bamboo
Answer : Option A
Explaination / Solution:
Sucker is underground shoot that some stage emerges above the soil surface and gives rise to a new plant. It is initially nourished by parent plant but later become independent.
Q9. The product of ecosystem processes are called as
Answer : Option A
Explaination / Solution:
The products of ecosystem processes are called as ecosystem services. Ecosystem services includes purification of air and water by forests and soil formation as well as nutrient cycles
Q10. Development of fruit without fertilization is called
Answer : Option D
Explaination / Solution:
Fruit formation without fertilisation results into seedless fruit. Parthenogenesis is development of new individual from unfertilised eggs. Parthenocarpy can be induced artificially using plant hormone auxin.
