14. Arrange the following in the decreasing order (most important first) of their importance, for the welfare of human society. Give reasons for your answer. Biogas, Citric acid, Penicillin and Curd
These can be arranged as Penicillin - Biogas- Curd- Citric acid.
Penicillin is an antibiotic which is used to cure many diseases like pneumonia. Thus it should be the most important.
Biogas serves as a source of clean fuel, so it is the second most important.
Curd comes next which is a nutritious milk product.
Citric acid is used in food processing industries. Thus, it is last in the list