In which way have microbes played a major role in controlling diseases caused by harmful bacteria?

Which one of the following pairs is correctly matched?

Medicines are either man-made (i.e.,synthetic) or obtained from living organisms like plants,bacteria,animals,etc.,and hence,the latter are called natural products. Sometimes,natural products are chemically altered by man to reduce toxicity or side effects. Write against each of the following whether they were initially obtained as a natural product or as a synthetic chemical: $(a)$ Penicillin $(b)$ Sulphonamide $(c)$ Vitamin-$C$ $(d)$ Growth hormone.

What is the role of bacteria present in the rumen of cattle?

Proteins that kill the same or closely related species of bacteria are called

Which of the following microbes is the source of the first antibiotic?