A Level Biology Practice Exam

Which characteristic defines xerophytes?

1. They thrive in aquatic environments

2. They have adaptations for surviving in dry habitats

3. They require high levels of humidity

4. They can only grow in temperate climates

The correct answer is: They have adaptations for surviving in dry habitats

Xerophytes are plant species that are specifically adapted to survive in environments with very little water, typically found in dry habitats such as deserts. These adaptations enable them to minimize water loss and maximize water retention. Common characteristics of xerophytes include thickened cuticles, reduced leaf area or modified leaves (like cacti with spines), deep root systems to reach underground water, and the ability to store water in their tissues. In contrast, the other options highlight characteristics that do not apply to xerophytes. For example, plants that thrive in aquatic environments or require high levels of humidity are not xerophytes, as they depend on abundant water availability. Similarly, the statement regarding growth only in temperate climates is misleading, since xerophytes can be found in a variety of climates, particularly arid ones rather than temperate zones. Thus, the defining characteristic of xerophytes revolves around their ability to thrive in dry conditions through numerous specialized adaptations.