The two most common root systems are

• A. Adventitious and Tap
• B. Taproot and Fibrous
• C. Fibrous and Tap
• D. Primary and Secondary

Answer: (C)

Two basic root architectures are being tested here: a taproot system, where one main downward-growing root is dominant and gives off lateral roots, and a fibrous root system, where many thin roots arise from the stem and form a dense network. The taproot pattern is common in many dicots, while the fibrous pattern dominates in monocots and many grasses. This pairing naming the two primary architectures is the standard way scientists classify root systems, so it best fits the question. Adventitious roots refer to roots that form from non-root tissues and can occur in either system, but they aren’t used to describe the main root architecture. Primary and Secondary describe growth stages or root orders, not distinct root system types.