Correct Option: B. low temperature Explanation of the Correct Answer Maize (Zea mays), commonly known as corn, is a warm-season crop that thrives in specific environmental conditions. The factors essential for maize production include temperature, humidity, and rainfall, but they must be within certain ranges to support optimal growth.

1. High Temperature: Maize requires warm temperatures for germination and growth. The ideal temperature range for maize growth is between 60°F (15°C) and 95°F (35°C). High temperatures promote photosynthesis and growth, leading to better yields. Therefore, high temperature is indeed essential for maize production.
2. Relative Humidity: This factor is crucial as it affects the plant's transpiration process. Maize requires a certain level of humidity to maintain water balance and nutrient uptake. High relative humidity can help reduce water loss through transpiration, which is vital during the growing season.
3. Adequate Rainfall: Water is essential for maize growth. Adequate rainfall ensures that the soil remains moist, which is necessary for seed germination, root development, and overall plant health. Insufficient rainfall can lead to drought stress, negatively impacting yield.
4. Low Temperature: This is the correct answer because low temperatures are detrimental to maize production. When temperatures drop below the optimal range, it can slow down germination, hinder growth, and even cause frost damage to the plants. Maize is not frost-tolerant, and exposure to low temperatures can lead to poor yields or complete crop failure.

Explanation of Why Other Options Are Incorrect or Weaker

• A. High Temperature: As explained, high temperatures are beneficial for maize growth, making this option incorrect.
• C. Relative Humidity: This factor is essential for maintaining the plant's water balance and supporting growth. Therefore, it is not an exception and is necessary for maize production.
• D. Adequate Rainfall: Water is critical for maize, and adequate rainfall is necessary for successful cultivation. This option is also not an exception.

Summary of Key Points

• Maize thrives in warm temperatures, ideally between 60°F and 95°F.
• High relative humidity supports water retention and nutrient uptake.
• Adequate rainfall is crucial for maintaining soil moisture and preventing drought stress.
• Low temperatures are harmful to maize, making them the exception in this context.

By understanding these factors, students can better appreciate the environmental requirements for successful maize production and the implications of climate on agricultural practices.