CBSE 12TH BIOLOGY - Online Test
Q1. Fleming, Chain and Florey were awarded the Nobel Prize in 1945 for discovery of
Answer : Option A
Explaination / Solution:
Fleming, Chain and Florey were awarded the Nobel Prize in 1945 for discovery of antibiotics. Antibiotics prevent the growth of bacteria and fungi.
Q2. Which one is most toxic
Answer : Option A
Explaination / Solution:
Out of the given gases carbon monoxide is the most toxic gas as it combine with hemoglobin present in blood and reduce the oxygen carrying capacity of blood.
Q3. Helium is used in Biolistic gun as
Answer : Option A
Explaination / Solution:
Biolistic gun is used to insert the foreign DNA into the target organism. The gene gun is utilized to bombard the plant cell wall with many DNA coated metal particles by using compressed helium as the propellant.
Q4. The process of evolution of different species in a given geographical area starting from a point and radiating to other geographical area is called
Answer : Option A
Explaination / Solution:
In evolutionary biology, adaptive radiation is a process in which organisms diversify rapidly from an ancestral species into a multitude of new forms, particularly when a change in the environment makes new resources available, creates new challenges, or opens new environmental niches.
Q5. Corm is a modification of
Answer : Option D
Explaination / Solution:
Corm is an organ of perenation and vegetative propagation consisting of a short erect fleshy swollen underground stem. It store food material.
Q6. Fundamental ecosystem services are taken as granted because
Answer : Option A
Explaination / Solution:
Researchers have put an average price tag of US $33 trillion a year on these fundamental ecosystems services, which is largely taken for granted because they are free. This service includes nature’s life support system without which life is not possible on this planet.
Q7. Which out of the following is advantage of chemical safety testing on transgenic animals?
Answer : Option C
Explaination / Solution:
Transgenic animals are made to carry gene that make them sensitive to toxic substance than non-transgenic animals and exposed to toxic substance. Toxicity testing in transgenic animals allows us to obtain results in less time.
Q8.
Statement I: Infection or diseases transmitted through sexual intercourse are called sexually transmitted disease or venereal disease.
Statement II: Tuberculosis is a sexually transmitted disease caused by bacteria.
Statement III: Hepatitis B is transmitted by use of contaminated water.
Answer : Option D
Explaination / Solution:
Infection or diseases transmitted through sexual intercourse are called sexually transmitted disease or venereal disease. Tuberculosis is not transmitted by sexual intercourse, so it is not a STD.
Hepatitis B infection is caused by the hepatitis B virus (HBV). The virus is passed from person to person through blood, semen or other body fluids. Common ways HBV is transmitted include: Sexual contact
Q9. Epiblast present in certain monocot embryo represents
Answer : Option A
Explaination / Solution:
Embryo of certain monocotyledonous seeds contain additional cotyledon besides one present in al monocots. This cotyledon represents the evolutionary stage of cotyledon formation from one to two.
Q10. Migration is an adaptation that should be categorised under
Answer : Option A
Explaination / Solution:
The organisms move away temporally from stressful habitat to more suitable habitat is called migration. Migration adaptation is a behavioral attribute.
