CBSE 12TH BIOLOGY - Online Test
Q1. CES stands for:
Answer : Option A
Explaination / Solution:
CES The Centre for Ecological Sciences, founded in 1983 with the support of the Ministry of Environment and Forests offers exciting opportunities for research in a variety of areas in ecology.
Q2. In which part of sperm, mitochondria are present?
Answer : Option B
Explaination / Solution:
Mitochondria are called power-house of the cell. Sperms need energy for active movement. Middle piece of sperm contain large number of mitochondria.
Q3. Sex determination in human being is
Answer : Option D
Explaination / Solution:
In human beings, a pair of X chromosome is found in female and presence of an X and Y chromosome are determinant of male characteristic.
Q4. Virus that kills bacteria are called
Answer : Option C
Explaination / Solution:
Bacteria eating virus are called Bacteriophage. Bacteriophage attach with body of bacteria and genetic material is transferred to bacteria where lot of bacteriophage are produced.
Q5. As per U.S. greenhouse gas emissions report which of the following accounted for the second largest percentage of greenhouse gases?
Answer : Option C
Explaination / Solution:
According to U.S. greenhouse gas emissions report methane (CH4CH4) accounted of the second largest percentage of greenhouse gases after Chlorofluorocarbon (CFCs).
Q6. Stanley Cohen and Herbert Boyer worked on which bacteria?
Answer : Option D
Explaination / Solution:
Stanley Cohen and Herbert Boyer worked on bacterium Salmonella typhimuriumin 1972 by isolating the antibiotic resistance gene by cutting out a piece of DNA from a plasmid which was responsible for conferring antibiotic resistance.
Q7. According to Neo-Darwinism, natural selection operates through
Answer : Option C
Explaination / Solution:
According to Neo-Darwinism, natural selection operates through differential reproduction. During sexual reproduction gametes are formed by meiosis division in which crossing over brings about change in traits that leads to variation for natural selection.
Q8.
Statement I: Asexual reproduction involves fusion of gametes.
Statement II: Asexually produced offspring are genetically identical.
Statement III: Asexual reproduction occurs in unfavorable condition only.
Answer : Option D
Explaination / Solution:
In asexual reproduction, fusion of gametes do not takes place and asexual reproduction occurs in favorable conditions. As fusion of gametes do not takes place, all the individuals are genetically identical to each other.
Q9. Which of the following is not a layer found in lakes?
Answer : Option B
Explaination / Solution:
Lentic zone is found in flowing terrestrial water such as rivers and streams. Lake stratification have limnetic, littoral and profundal zone only.
Q10. Alpha lactalbumin present in milk is
Answer : Option A
Explaination / Solution:
The milk produced by transgenic cow contain a protein called alpha lactaalbumin. The milk containing this protein is more suitable for babies as compare to normal cow’s milk.
