Answer: Roots.
- A Leaves
- B Roots
- C Stems
- D Flowers
Correct answer: B. Roots
Explanation: Mycorrhiza is a mutualistic symbiosis between fungi and plant roots, enhancing nutrient (especially phosphorus) absorption.
Sewage passes through physical removal (primary), then aerobic biological treatment where microbes form flocs that consume organic matter (secondary); the settled activated sludge is then digested anaerobically to produce biogas - a deliberate switch from aerobic to anaerobic conditions between stages.
Concept context
Microorganisms in food, medicine, sewage treatment, biocontrol, and biofertilizers