Xerophytes are plants that have adapted to survive in environments with limited water availability. The correct answer, option 1, states that xerophytes thrive in hot and arid conditions. This means that xerophytes are well-suited to areas that are both hot, meaning they have high temperatures, and arid, meaning they have very little moisture or rainfall.

Option 2, cool and wet conditions, is not suitable for xerophytes. Xerophytes are adapted to conserve water and are not well-suited to cool and wet environments, which typically have abundant rainfall and higher levels of humidity.

Option 3, hot and wet conditions, is also not suitable for xerophytes. While hot conditions may be tolerated by some xerophytes, they are not adapted to thrive in wet environments with high levels of moisture.

Option 4, cool and arid conditions, is not the correct answer. Xerophytes are adapted to survive in hot and arid conditions, not cool and arid conditions.