Living Environment Regents Practice Test

How does the antifreeze protein gene contribute to the survival of icefish?

1. It allows them to absorb oxygen directly from water

2. It enables them to withstand freezing temperatures in their habitat

3. It helps them to grow faster

4. It facilitates reproduction in cold environments

The correct answer is: It enables them to withstand freezing temperatures in their habitat

The antifreeze protein gene is essential for the survival of icefish because it plays a critical role in enabling these fish to withstand freezing temperatures in their cold aquatic habitats. Icefish are found in frigid waters, particularly in the Southern Ocean around Antarctica, where the temperature can drop below the freezing point of saltwater. The antifreeze proteins produced by these fish prevent the formation of ice crystals in their bodies, thus allowing them to survive and thrive in extreme cold without freezing. This adaptation is vital for their survival, as it allows them to exploit a niche that few other fish can inhabit. The other options do not accurately reflect the role of the antifreeze protein gene. For instance, while oxygen absorption is crucial for aquatic life, it is not directly related to the function of antifreeze proteins. Similarly, the antifreeze proteins do not contribute to faster growth or reproduction in cold environments; their primary function is to provide protection against freezing conditions.