CBSE 12TH BIOLOGY - Online Test
Q1. Adaptive ability is inherited because
Answer : Option D
Explaination / Solution:
An adaptive behavior is a behavior which contributes directly or indirectly to an individual's survival or reproductive success and is thus subject to the forces of natural selection.
The adaptive ability of an organism is inherited to their next generation because it has genetic basis. The adaptive traits arise due to change in gene.
Q2. Preventive birth control measure is
Answer : Option B
Explaination / Solution:
Preventive birth control measure is preventing sperms from entering the uterus. It includes periodic absentee, coitus interrupts etc.
Q3. Animals giving birth to young ones are called as
Answer : Option A
Explaination / Solution:
Animals reproduce sexually either by producing fertilized egg or by giving birth young ones directly. The viviparous (young one producing) is more evolved method of sexual reproduction.
Q4. Write and codon for anticodon on the t-RNA
Answer : Option B
Explaination / Solution:
The codon for anticodon UCA on t-RNA is AGU. U bonds with A and G bonds with U in RNA. t-RNA carries specific amino acids to form protein molecules.
Q5. Oogenesis starts
Answer : Option B
Explaination / Solution:
In female baby, oogenesis starts before the birth of baby after forming primary oocyte. Further development to ovum occurs after attaining puberty.
Q6. Deforestation is responsible for
Answer : Option B
Explaination / Solution:
Forests are habitat of large number of plants and animals along with microbes. Deforestation causes loss of habit and loss of speies living in that area that results into co-extinction.
Q7. How is extinction represented in a tree diagram?
Answer : Option B
Explaination / Solution:
In a tree diagram, the extinction is represented as a branch ends that further do not divide any more. Extinction may be due to changed climatic condition or loss of ecological niche.
Q8. Which of the following is a living fossil?
Answer : Option D
Explaination / Solution:
Cycas, a gymnosperm is called the living fossil because they have been evolved in Jurassic period and still survive in present climatic condition.
Q9. Which one is not a natural methods birth control
Answer : Option C
Explaination / Solution:
Tubectomy is not a natural method of birth control. In tubectomy method fallopian tube of female is cut and tide to prevent ovulation. To abstain, coitus interrupts and rhythm period is natural method of birth control.
Q10. During protein synthesis, AUG functions as the initiator codon in mRNA. What should be the anticodon on the t-RNA molecule that picks up and brings the amino acid specified by this codon?
Answer : Option A
Explaination / Solution:
The anticodon on the t-RNA corresponding to AUG initiator codon on mRNA is UAC as A bonds with U and G bonds with C in RNA. Thymine (T) is absent in RNA.
