Solution

The correctly matched triplets are AEI, BDH and CFG. AEI: A introduces the enzyme 'SIRT1' and ends with 'be'. 'Be' must be followed by a past participle or a present participle. Only E satisfies this grammatical condition. E elaborates that the enzyme regulates 'metabolic activities' and ends with the conjunction 'and'. I adds to this list by mentioning 'ageing'. BDH: B introduces the 'lagoons' of Lakshadweep. D carries this forward, stating that the lagoons house a 'stunningly colourful world'. H carries this further forward by elaborating that the colours include shades of 'red, pink, yellow and blue'. CFG: C introduces that the purpose of the constitution was to alter relationship between 'individual' and ends with the conjunction 'and'. F carries it forward and says 'state'. F ends with the adjective 'colonial' and must be followed by a noun which can be qualified by the same. G satisfies this grammatical condition; 'regime' acts as a noun. Amongst these, only AEI and CFG are mentioned in the given options. The other triplets are incorrectly matched.