CBSE 12TH BIOLOGY - Online Test
Q1. What's the difference between natural selection and sexual selection?
Answer : Option A
Explaination / Solution:
Natural selection is the survival of members of species having some new traits that may help the organism in given surrounding. Sexual selection is a kind of natural selection as mating between similar organisms only leads to reproduction.
Q2. Which of the following is not a categories of contraceptive method
Answer : Option D
Explaination / Solution:
Artificial insemination is not a contraceptive device. It is a assisted reproductive technologies for infertile people. Natural method, barrier method and surgical methods are categories of contraceptive method.
Q3. The human genome contains __________ nucleotide bases.
Answer : Option D
Explaination / Solution:
Important Features of Human Genome:
- The human genome contains 3164.7 million nucleotide bases.
- The average gene consists of 3000 bases, but gene size vary greatly (the largest human gene is dystrophin containing 2.4 million bases).
- The total number of genes in the genome is estimated at 30,000 and all (99.9 percent) nucleotide bases are exactly the same in all people
- Functions of about 50% of the discovered genes are still unknown.
- Less than 2% of the genes of the genome codes for proteins.
- Chromosome1 has most genes (2968) and the Y has the fewest (231).
Q4. Which of the following hormone is produced in female only during pregnancy?
Answer : Option A
Explaination / Solution:
Relaxin is produced by corpus leteum and is responsible for the inhibition of uterine contraction. It also helps in dilation of the cervix. This hormone is produced only during pregnancy.
Q5. Natural selection is a process in which heritable variations enabling better survival are enabled to
Answer : Option A
Explaination / Solution:
Natural selection is a process in which heritable variations enabling better survival are enabled to reproduce and leave greater number of progeny in the habitat to increase in number faster than other species.
Q6. Name the spermicidal cream developed by Central Drug Research Institute (Lucknow), India.
Answer : Option A
Explaination / Solution:
Spermacid
Q7. Gel electrophoresis is used for
Answer : Option B
Explaination / Solution:
Gel electrophoresis is used to separate macromolecules like DNA, RNA and proteins. DNA fragments are separated according to their size. Proteins can be separated according to their size and their charge (different proteins have different charges).
This is an important tool to study the genome of an individual.
Q8. The …….. is the sexual intercourse between male and female sex.
Answer : Option D
Explaination / Solution:
Transfer of male gametes (sperm) into female genital tract occurs during sexual intercourse that may leads to fertilisation of ovum for pregnancy. Sexual intercourse is called as coition or coitus.
Q9. Grow slower in new habitat is
Answer : Option D
Explaination / Solution:
Variation due to mutation or variation due to recombination during gametogenesis results in changed frequency of genes and alleles in future generation which results into stabilization and directional change in which more individual acquire mean character value.
Q10. Natural method of contraception works on the principle of
Answer : Option B
Explaination / Solution:
Natural method of contraception works on the principles of avoiding meeting of ovum and sperm for fertilisation. Ovum is released in the middle of menstrual cycle, avoiding sex during that interval is necessary in this method.
