पेनिसिलिन की खोज किसने की थी, जो आधुनिक चिकित्सा में इस्तेमाल होने वाला पहला प्रभावी एंटीबायोटिक बना?

Which of the following is CORRECT regarding the composition of viroids?

Why can yeast not produce alcoholic beverages with an alcohol content higher than ~13% naturally?

Which staining technique is used to differentiate bacteria into gram-positive and gram-negative based on their cell wall properties?