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
The decreasing order of importance for the welfare of human society is:
1. Penicillin – Most important because antibiotics have greatly improved our capacity to treat deadly diseases such as plague, whooping cough, diphtheria and leprosy, which used to kill millions all over the globe. Today, we cannot imagine a world without antibiotics. They have played a major role in controlling infectious diseases and saving human lives.
2. Biogas – Second in importance as it serves as a source of energy, especially in rural areas. Methanogens produce methane (biogas) while degrading plant waste. Biogas production also helps in waste management and provides an eco-friendly energy alternative.
3. Curd – Third in importance as it provides nutrition to humans daily. Lactic acid bacteria (LAB) grow in milk to convert it into curd, which is a widely consumed food product providing essential nutrients.
4. Citric acid – Least important among the four as it is primarily an industrial chemical. Aspergillus niger (a fungus) produces citric acid for commercial and industrial production. While useful, it is not as critical for human survival as the others.
Explanation
This question from NCERT Class 12 Biology Chapter 8 (Microbes in Human Welfare) tests students' understanding of the relative importance of different microbial products. The ranking is based on the impact each product has on human survival and welfare: Penicillin saves lives from deadly diseases (highest importance), Biogas provides energy and waste management, Curd provides daily nutrition, and Citric acid is primarily an industrial chemical (lowest importance).
Solution Steps
Step 1: Analyze the role of each product in human welfare based on the context
Step 2: Rank Penicillin first as it saves millions of lives from deadly diseases
Step 3: Rank Biogas second as it provides energy and waste management benefits
Step 4: Rank Curd third as it provides daily nutrition
Step 5: Rank Citric acid last as it is primarily an industrial chemical with less direct impact on human survival