The growth of mucor on a piece of bread is?

Step 1: Analyze the question The question asks what mode of nutrition or relationship Mucor shows when it grows on bread.

Step 2: Explain the concept Mucor is a fungus, commonly called bread mould. Fungi have no chlorophyll, so they cannot make their own food. Mucor secretes digestive enzymes onto dead organic matter (like stale bread), breaks it down outside its body, and then absorbs the soluble nutrients. This mode of feeding is called saprophytism, and the organism is a saprophyte.

Step 3: Check each option

• A. Scavenging: This is when animals (like vultures or hyenas) feed on dead animal remains or leftovers by eating them. Mucor does not ingest food; it digests externally and absorbs. So this is wrong.
• B. Commensalism: This is a relationship between two living organisms where one benefits and the other is unaffected. Bread is not a living organism, so this is wrong.
• C. Autotrophism: This means making one's own food (e.g., by photosynthesis). Mucor has no chlorophyll, so this is wrong.
• D. Saprophytism: Feeding on dead organic matter by external digestion and absorption. This fits Mucor on bread perfectly.

Step 4: Answer The correct option is D. saprophytism.

Exam tip: Remember "Sapro = Spoiled/dead." Whenever you see a fungus (Mucor, Rhizopus, mushroom) growing on dead or decaying matter such as bread, wood, or rotting fruit, think saprophyte. If the fungus is feeding on a living host, think parasite instead (e.g., Puccinia on wheat).