Tertiary roots are

The correct answer is ageotropic.

To understand why tertiary roots are ageotropic, let us break down the concept of geotropism (also known as gravitropism) in plant roots:
1. Geotropism refers to the growth movement of a plant part in response to the force of gravity.
2. Primary roots grow directly downward into the soil, along the direction of gravity. Because they grow toward the gravitational pull, they are described as positively geotropic.
3. Secondary roots arise from the primary root and grow horizontally or at an angle relative to the pull of gravity. They are described as plagiogeotropic.
4. Tertiary roots arise from the secondary roots. These roots grow in various directions to maximize the absorption of water and nutrients from different soil zones. Because their growth direction is completely unaffected by the force of gravity, they show no gravitational orientation and are described as ageotropic (or insensitive to gravity).