Zebra mussels multiply and spread so fast because:

• A. They can survive out of water
• B. They commonly adhere to boats, so they move around and disperse eggs
• C. They are strong swimmers
• D. They have few natural predators

Answer: (B)

Zebra mussels are particularly adept at spreading rapidly due to their behavior of adhering to boats and other surfaces, which enables them to be transported over long distances. Once attached to a moving vessel, they can easily reach new freshwater habitats where they can establish themselves and reproduce. The transportation method significantly increases the likelihood of their eggs being dispersed to new locations, contributing to their population growth in various water bodies.

Adhering to boats not only assists in their migration but also allows them to successfully capitalize on favorable conditions in novel environments. This trait, combined with their prolific breeding capabilities, makes them a significant ecological concern.