NCERT Class 12 Biology Optional Questions with Answers
42 The sequence of nitrogen bases in a # segment of a coding strand of DNA is ’ AATGCTTAGGCA. What will be the sequence of nitrogen bases in the wRNA transcribed by it?
Answer: AAU GCU UAG GCA
43 Which one of the following impurities is easiest to remove from wastewater?
Answer: Suspended solids
44 Nuisance growth of aquatic plants and bloom-forming algae in natural waters is generally due to high concentrations of
46 The sequence of communities of primary succession in water is
Answer: phytoplankton, rooted submerged hydrophytes, floating hydrophytes, reed swamp, sedges, meadow and trees.
47 Catalytic converters are fitted into automobiles to reduce emission of harmful gases. Catalytic converters change unbumt hydrocarbons into
Answer: carbon dioxide and water
49 The central dogma of molecular biology (genetic information flow) was modified by the discovery of
Answer: Reverse transcriptase
50 The human chromosome with the highest and least number of genes in them are respectively
Answer: Chromosome 1 and Y