What is the thick-walled protective spore that forms inside a bacterial cell and resists harsh conditions?

• A. Endospore
• B. Capsule
• C. Pili
• D. Monerans

Answer: (A)

Endospore formation is a bacterial survival strategy. Certain bacteria respond to stress, like nutrient shortage, by forming a thick-walled, protective spore inside the cell. This endospore has a durable coat and a dehydrated core that make it highly resistant to heat, drying, chemicals, and radiation, allowing the organism to endure harsh conditions until conditions improve. When favorable conditions return, the endospore can germinate back into a regular, active cell. A capsule is an external polysaccharide layer that helps with attachment and immune evasion, not a dormant protective structure; pili are hair-like appendages used for adhesion or DNA transfer; and monerans is an old term for bacteria, not a cellular structure.