Question

1. infrared radiation is characterized by: being visible to human eyes having a frequency lower than red light generating no heat energy existing only in laboratory conditions

Explanation:

Infrared radiation is part of the electromagnetic - spectrum. It has a frequency lower than that of red light. It is not visible to human eyes, it can carry heat energy, and it exists in nature, not just in laboratory conditions.

Answer:

B. Having a frequency lower than red light