What is one characteristic of unstable rubble regarding stabilization?

The characteristic that unstable rubble will not stabilize or undergo binding highlights the inherent challenges associated with this type of substrate in coral restoration efforts. Unstable rubble, often composed of loose materials and debris, lacks the cohesion necessary for stabilization, making it difficult for corals to anchor effectively. This instability poses a significant barrier to coral growth as corals typically require a firm substrate for attachment and growth.

In contrast, options suggesting that it will undergo binding or is already stabilized by macroalgae do not accurately reflect the conditions of unstable rubble. Such rubble often needs external intervention, such as cementation, to promote stabilization and create a suitable habitat for coral larvae. Therefore, understanding the nature of unstable rubble is crucial for implementing effective coral restoration techniques, as it informs the need for additional measures to foster a stable environment conducive to coral growth.