CBSE 12TH BIOLOGY - Online Test
Q1. The anterior most portion of the external genitalia of female which is fatty area covered with skin and pubic hair is called
Answer : Option B
Explaination / Solution:
The mons pubis is the rounded eminence, made by fatty tissue beneath the skin, lying in front of the pubic symphysis. A few fine hairs may be present in childhood; later, at puberty, they become coarser and more numerous. The upper limit of the hairy region is horizontal across the lower abdomen.
Q2. The pairs of chromosomes present in human beings somatic cells are
Answer : Option C
Explaination / Solution:
In human beings 23 pairs of chromosomes are present out of which 22 pairs are called autosomes and 1 pair is called sex chromosome.
Q3. Rotenone is
Answer : Option C
Explaination / Solution:
Rotenone is a naturally occurring chemical with insecticidal properties, obtained from the roots of the several tropical and subtropical plant species.
Q4. The cardiovascular centre is located in :
Answer : Option A
Explaination / Solution:
The cardiovascular centre is a part of the human brain responsible for the regulation of the rate at which the heart beats through the nervous and endocrine systems. It is found in the medulla oblongata.
Q5. Bioremediation of Phenol, one of the most common environmental pollutants is reported to be assisted by :
Answer : Option A
Explaination / Solution:
Bioremediation is a waste management technique that involves the use of organisms to remove or neutralize pollutants. Bioremediation of phenol is carried out using earthworms and bacteria.
Q6. During agarose gel electrophoresis DNA fragments moves towards anode. This is because
Answer : Option B
Explaination / Solution:
To separate DNA using agarose gel electrophoresis, the DNA is loaded into pre-cast wells in the gel and a current applied. The phosphate backbone of the DNA (and RNA) molecule is negatively charged, therefore when placed in an electric field, DNA fragments will migrate to the positively charged anode.
Q7. Which one of the following experiments suggests that simplest living organisms could not have originated spontaneously from non-living matter
Answer : Option D
Explaination / Solution:
Simplest organisms could not have originated spontaneously from non-living matter. This can be shown as meat was not spoiled when heated and kept sealed in vessels.
Q8. Micropropagation is technique
Answer : Option C
Explaination / Solution:
Micropropagation is the technique of growing large number of plantlets using small parts of plants. Plant parts are totipotent or able to generate whole plant with small portion. This process is also called as tissue culture in which true type of plants.
Q9. Which of the following represents an incorrect feature of ecological succession:
Answer : Option A
Explaination / Solution:
Ecological succession gradually results into gradual increase in the biomass as new species having complex plant body replace the older species. Thus, the biomass increase at each stage of succession.
Q10. Biopiracy is
Answer : Option A
Explaination / Solution:
Biopiracy describes a practice in which indigenous knowledge of nature, originating with indigenous peoples, is used by others for profit, without permission from and with little or no compensation or recognition to the indigenous people themselves.
