a) Minerals are continuouosly absorbed by plants.
b) Minerals are returned to soil by tertiary consumers.

Explanation

**Step-by-Step Text Solution:**

1. **Understanding the First Statement:**
- The first statement claims that "minerals are continuously absorbed by plants." This is true. Plants absorb minerals from the soil through their roots. These minerals are essential for various physiological processes in plants, including growth and development.

2. **Understanding the Second Statement:**
- The second statement asserts that "minerals are returned to soil by tertiary consumers." This statement is incorrect. While it is true that minerals do return to the soil, this process does not occur directly through tertiary consumers.

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