WAEC Biology 2025 Theory — Question 6

Model answer

(i) Saprophytes are organisms that feed on dead and decaying organic matter, using extracellular digestion. (ii) Examples: Rhizopus, mucor, penicillium, some bacteria (any two). (iii) Mode of feeding: Saprophytes release digestive enzymes onto the substrate to break down complex organic substances into simpler compounds, which they then absorb. (iv) Economic importance: Decomposition - breakdown of dead organisms, aiding nutrient recycling; Soil fertility - enhances soil quality through humus formation; Bioremediation - degrade pollutants and clean up the environment.