CBSE 12TH BIOLOGY - Online Test
Q1. Genotype is the
Answer : Option A
Explaination / Solution:
Genotype is the genetic combination of an individual. TT and Tt are genotypically different but phenotypically appear tall.
Q2. The puffed-up appearance of dough is due to production of
Answer : Option B
Explaination / Solution:
The puffed-up appearance of dough is due to production of gas. Baking soda (sodium hydrogen carbonate) on heating release carbon dioxide gas along with sodium carbonate.
Q3. Term acid rain was coined for the first time by
Answer : Option A
Explaination / Solution:
Robert August Smith was a Scottish chemist, who investigated numerous environmental issues. He is known for his research on air pollution in 1852, in the course of which he discovered what came to be known as acid rain. He is sometimes referred to as the 'Father of Acid Rain'.
Acid rain occurs due to presence of Sulphur dioxide and nitrogen oxide in atmosphere.
Q4. Some scientist consider virus as living entities because they can
Answer : Option D
Explaination / Solution:
Virus is called as borderline of living and non-living. Viruses act as living one when inside the other living organism and reproduce very fast. When outside the living body, virus behaves as molecules without any sign of living.
Q5. Host cell membrane can be made permeable by
Answer : Option B
Explaination / Solution:
CaCl2 can be used to make the bacterial cell a permeable cell, and by introducing these cells (after CaCl2 being placed into the mixture of bacterial cells), a plasmid for ampicillin resistance can be transformed into the bacteria. The standard method for making the bacteria permeable to DNA involves treatment with calcium ions.
Q6. According to abiogenesis life originates from
Answer : Option A
Explaination / Solution:
According to abiogenesis theory of origin of life, life originated from non-living matter like gases, inorganic substance and water at particular temperature and pressure.
Q7. Bt toxin is obtained from
Answer : Option A
Explaination / Solution:
Bt toxin is obtained from Bacillus thuringiensis bacterium that can kill certain insects like tobacco budworm, armyworm, beetles and flies.
Q8. Which one is not a sexually transmitted disease?
Answer : Option D
Explaination / Solution:
Diseases acquired during sexual intercourse are called sexually transmitted disease. Hepatitis-B is not transmitted through coitus.
Q9. Examples of artificial ecosystem is/are:
Answer : Option A
Explaination / Solution:
Artificial ecosystems are man-made ecosystem. Crop field and aquarium are examples of artificial ecosystem as they are man-made.
Q10. Alzheimer disease in humans is associated with the deficiency of
Answer : Option D
Explaination / Solution:
Alzheimer disease is a neurological disorder in which the death of brain cells causes memory loss and cognitive decline. It is caused in human due to deficiency of acetylcholine.
