In the question below, a sentence is given with four words highlighted in bold, followed by options that provide a replacement for each word. From the options, choose the word that must be replaced with its appropriate replacement. If all the highlighted words are correct and none need to be replaced, or if the incorrect word is not provided with an appropriate replacement, choose option (e),
i.e. ‘None of the above’. The biggest asteroid impacts would have swathed our globe in recalcitrant rock vapour, boiling the oceans dry and fumigating the surface worldwide.