What do mycorrhizal fungi release that helps break down substances trees can't use without help?

• A. Enzymes
• B. Acids
• C. Sugars
• D. Bases

Answer: (B)

Mycorrhizal fungi release organic acids into the soil around the roots. These acids lower the rhizosphere pH and help dissolve minerals, making nutrients like phosphorus and trace elements soluble and accessible to the tree. That acid-mediated mineral solubilization is the key way these fungi unlock nutrients the tree can’t get on its own. Enzymes do help break down some materials, but the question focuses on what is released to make minerals available, which is accomplished best by acids. Sugars are energy sources, and bases aren’t the typical mechanism here, so acids are the fitting answer.