What type of roots develop from stems or leaves rather than from another root?

Adventitious roots are specialized roots that emerge from non-root tissues, such as stems or leaves. This characteristic allows plants to adapt to various environmental conditions, support their structure, and increase stability. For example, in some plants, when a stem comes into contact with the soil, adventitious roots can form to help anchor the plant more securely or to reach out for water and nutrients.

In contrast, tap roots are characterized by a primary root that grows downward and facilitates deep soil penetration, while fibrous roots form a dense network of similar-sized roots that spread out from the base of the plant. Radicle roots refer specifically to the first root that develops from a germinating seed, serving as a foundational root system for young plants. Thus, the definition and function of adventitious roots distinctly highlight their ability to arise from non-root tissues, making them the correct answer in this context.