| 1. | D is the acidic amino acid - glutamic acid |
| 2. | C is an aromatic amino acid - tryptophan |
| 3. | A is the C-terminal amino acid and D is N terminal amino acid |
| 4. | A is the sulphur containing amino acid-methionine |
| 1. | due to some defect like aspermia in man |
| 2. | due to the genetic makeup of the particular sperm which fertilizes the egg |
| 3. | due to the genetic makeup of the egg |
| 4. | due to some defect in the women |
| 1. | Guard cells invariably possess chloroplasts and mitochondria |
| 2. | Guard cells are always surrounded by subsidiary cells |
| 3. | Stomata are involved in gaseous exchange |
| 4. | Inner walls of guard cells are thick |
| Animal | Excretory organs | Excretory product | |
| 1. | Labeo (Rohu) | Nephridial tubes | Ammonia |
| 2. | Salamander | Kidney | Urea |
| 3. | Peacock | Kidney | Urea |
| 4. | Housefly | Renal tubules | Uric acid |