Wondering if it's only me or if there are others who feel answers to Q67 and 74 require a relook from FIAS faculty. Q67 doesn't matter much but Q74 is a probable one for this year's Prelims. Sharing my obs here:
In Q74, I am of the opinion that Large hydro does not constitute Renewable Energy as the answer seems to suggest. In fact, in one of the UPSC Prelims papers' from '18/'19 it was implicitly asked if large hydro does actually constitute renewable energy or not. This was a question around our INDCs. &UPSC did not consider it Renewable as far as I remember. Even this year's Economic survey includes two graphs and a table that explicitly mentions large hydro as a separate component in our energy mix. It forms a part of non-fossil energy sources, agreed, but not renewable as far as I understand. Would appreciate it if somebody can clarify this. Seems to be relevant for this year's pre.
In 67, I feel the answer should be D. While it's true that yeast is added to let the dough rise, it shouldn't discard the use of bacteria. In fact, bacteria are actually used in the preparation of a lot of specialty bread preparations, just like cheese. Can also be fact-checked with a quick google search. Also as a side logic, one may see the use of bacteria to aid gut digestion.