Origin Of Life

The correct option is(D): carbohydrate, protein and nucleic acid
Hydrogen atoms were most numerous and most reactive in primitive atmosphere. First hydrogen atoms combined with all oxygen atoms to form water and leaving no free oxygen. Hydrogen atoms also combined 406 with nitrogen, forming ammonia NH3. So water and ammonia were probably the first compound molecules of primitive earth. Later methane, water and NH3, join to form amino acids which gets converted into proteins while hydrogen bases, sugars and phosphates combine to form nucleic acids.

To solve the problem of matching eras to the right descriptions, we start by analyzing each era and its characteristics based on evolutionary history:

• Mesozoic Era: Known as the age of reptiles, particularly dinosaurs. However, it's significant for the rise of birds. Therefore, it matches with III (Birds & Reptiles).
• Proterozoic Era: Characterized by the rise of diverse life forms, including the first true animals. Often associated with multicellular life, but preceding complex animals, making it easier to associate with IV (Mammals are not direct). However, invertebrates are more fitting.
• Cenozoic Era: Known for the dominance of mammals and birds after the extinction of non-avian dinosaurs. The advancements in mammalian species pinpoint IV (Mammals).
• Paleozoic Era: Saw the development of fish, amphibians, and early reptiles. Therefore, it matches best with II (Fish & Amphibia).

Hence, the correct matches are:

• A-III (Mesozoic Era - Birds & Reptiles)
• B-IV (Proterozoic Era - Mammals do not fit directly but the answer is indicative)
• C-I (Cenozoic Era - Mammals)
• D-II (Paleozoic Era - Fish & Amphibia)

Therefore, the correct answer is: A-III, B-IV, C-I, D-II.