CBSE 12TH BIOLOGY - Online Test
Q1. Assertion: Each spermatogonium is diploid and contains 46 chromosomes.
Reason: Some spermatogonia, primary spermatocytes complete the meiotic division to form four haploid cells.
Answer : Option D
Explaination / Solution:
Each spermatogonium is a diploid cell and contains 23 pairs of chromosomes. Some spermtogonia, called primary spermatocytes complete the first meiotic division to form two haploid cells. So, assertion is correct but reason is incorrect.
Q2. All are inorganic pollutants except
Answer : Option D
Explaination / Solution:
Inorganic Pollution are things found naturally but because of human production of goods have been altered to drastically increase the amount of them in the environment (some examples include arsenic, lead, as well as many different air pollutants). Examples of Inorganic Pollution: Lead, Zinc, Copper, Cadmium.
Motor oil is an organic pollutant.
Q3. What's the difference between genetic drift and change due to natural selection?
Answer : Option A
Explaination / Solution:
Genetic drift and change due to natural selection are different as genetic drift does not involve completion between the members of a species but in natural selection there is completion between members.
Q4. In human female, menstruation can be deferred by the administration of
Answer : Option D
Explaination / Solution:
Menstruation can be deferred by the administration of combination of hormone estrogen and progesterone. Follicle stimulating hormone and luteinizing hormone are produced during ovulation.
Q5. What is the purpose of the Human Genome Project?
Answer : Option C
Explaination / Solution:
The Human Genome Project was an international research effort to provide a complete and accurate sequence of the 3 billion DNA base pairs that make up the human genome and to find all of the estimated 20,000 to 25,000 human genes.
The Project was coordinated by the National Institutes of Health and the U.S. Department of Energy.
Q6. Beginning of menstrual cycle is called as
Answer : Option D
Explaination / Solution:
At puberty, menstrual cycle begins in girls. The beginning of menstrual cycle is called menarche. It starts at the age of about 12 to 13 years in girls.
Q7. The age of rock is calculated on the basis of
Answer : Option C
Explaination / Solution:
The age of rock is calculated on the basis of number of strata present.Contained within the rock strata is evidence that the region was intensely dry 15,000 years ago. Having more number of strata means older the rock.
Q8. Oral contraceptives for the female containing non-steroidal preparation with very few side effects and high contraceptive value, “once a week pill”.
Answer : Option A
Explaination / Solution:
Saheli is oral contraceptive for the female containing non-steroidal preparation with very few side effects and high contraceptive value. It is once a week pill.
Q9. Human genome project was closely associated with the rapid development of a new area in biology called as
Answer : Option D
Explaination / Solution:
Human genome project was associated with the rapid development of new area of biology called as bioinformatics. This branch of biological science is used to known the sequence of gene on Chromosome of living organisms.
Q10. The period between fertilization and birth is called as
Answer : Option C
Explaination / Solution:
The period between fertilisation of ovum till the birth of will developed baby is called gestation period. It is about 10 months in human female.
