Question

allelopathy is a natural phenomenon in which ______.
a. one plant secretes chemicals that inhibit root growth or seed germination of other seeds
b. two plants grow better when planted close to one another
c. bright light produces disease symptoms in plants
d. plants grow toward sunlight

Explanation:

To solve this, we analyze each option based on the definition of allelopathy. Allelopathy involves one plant releasing chemicals that affect other plants (usually inhibiting growth/germination).

• Option a: Matches the definition as it describes one plant secreting chemicals to inhibit other plants' growth/germination.
• Option b: Describes mutualistic or synergistic growth, not allelopathy.
• Option c: Involves light and disease, unrelated to allelopathy.
• Option d: Describes phototropism, not allelopathy.

Answer:

a. one plant secretes chemicals that inhibit root growth or seed germination of other seeds