NCERT Class 12 Biology General Awareness Questions with Answers
63 Diaphragms are the contraceptive devices used by females. Choose the correct option about them.
Answer: All of these.
64 The most accepted line of descent in human evolution is
Answer: Ramapithecus → Homo habilis → Homo erectus → Homo sapiens
65 In 1953 S. L. Miller created primitive earth conditions in the laboratory and gave experimental evidence for origin of first form of life from preexisting non-living organic s molecules. The primitive earth conditions created include
Answer: high temperature, volcanic storms, reducing atmosphere containing CH4, NH3 etc.
66 Appearance of antibiotic-resistant bacteria is an example of
Answer: pre-existing variation in the population
67 When ‘Aa’ is crossed with ‘aa’, (A is dominant over a)
Answer: 50% of offspring will have dominant phenotype and 50% will have recessive phenotype.
68 The possibility of all genotypes of offspring in a genetic cross is calculated by a graphical representation which was developed by
Answer: Reginald Punnett
69 Study the pedigree chart given Select the correct option about the conclusion.
Answer: It is an autosomal recessive trait.
70 Mother and father of a person with ‘O’ blood group have ‘A’ and ‘B’ blood group respectively. What would be the genotype of both mother and father?
Answer: Both mother and father are heterozygous for ‘A’ and ‘B’ blood group, respectively.