CBSE 12TH BIOLOGY - Online Test
Q1. Darwin judged the fitness of an individual by
Answer : Option C
Explaination / Solution:
Darwin judged the fitness of an individual by number of offspring the individual produce in particular niche. More the viable offspring formed the more fit the organism in that surrounding.
Q2. Which of the following is not method of asexual reproduction
Answer : Option A
Explaination / Solution:
Conjugation is the mode of sexual reproduction in amoeba and some other Moneras. Cutting, grafting and budding are the mode of asexual reproduction without gametes formation.
Q3. Which one of the following is the most important service provided by ecosystems:
Answer : Option C
Explaination / Solution:
Ecosystem services includes all activities performed by nature to benefits of human beings. The most important ecological service includes soil formation. Soil is essential for growth of plants that provide food to all living forms.
Q4. Dolly sheep is made by implanting oocyte at what stage
Answer : Option C
Explaination / Solution:
Dolly (5 July 1996 – 14 February 2003) was a female domestic sheep, and the first mammal cloned from an adult somatic cell, using the process of nuclear transfer.
Dolly had three mothers (one provided the egg, another the DNA and a third carried the cloned embryo to term). She was created using the technique of somatic cell nuclear transfer, where the cell nucleus from an adult cell is transferred into an unfertilized oocyte (developing egg cell) that has had its cell nucleus removed.
The hybrid cell is then stimulated to divide by an electric shock, and when it develops into a blastocyst it is implanted in a surrogate mother. Dolly was the first clone produced from a cell taken from an adult mammal.
Q5. In India, there is rapid decline in infant mortality rate and MMR due to
Answer : Option B
Explaination / Solution:
The rapid decline in IMR and MMR is due to more attention on RCH program that provide proper immunization before and after the birth of baby providing assistance in delivery and child care, all these together result into decline in dearth of infants and mother during pregnancy.
Q6. The cleavage of the zygote or earlier stage of its development into two or more units to form many embryo is called as
Answer : Option B
Explaination / Solution:
Zygote may divides into two or more parts to develop multiple embryos. The formation of more than one embryo inside the same ovule by cleavage is called cleavage polyembryony.
Q7. Diapause is shown by
Answer : Option C
Explaination / Solution:
Dispause is a period during which growth and development is suspended and physiological activity is diminished to adverse environmental condition. Diapause occurs in monarch butterfly and silk worm.
Q8. A tumor enclosed within a capsule is termed
Answer : Option B
Explaination / Solution:
A tumor enclosed within a capsule is called benign tumor. Benign tumors normally remain confined to their original location and do not spread to other parts of the body and cause little damage.
Q9. The code AUG stands for
Answer : Option B
Explaination / Solution:
The start codon is the first codon of a messenger RNA (mRNA) transcript translated by a ribosome. The start codon always codes for methionine in eukaryotes and a modified Met (fMet) in prokaryotes. The most common start codon is AUG.
Q10. Hybrid vigour is mostly due to
Answer : Option C
Explaination / Solution:
Hybrid vigour is mostly due to heterozygosity of traits. The hybrid contain genome from both the parents that make them more vigorous.
