Answer:
High Frequency.
Step-by-step explanation:
Two examples of high frequency waves that are harmful to life is ultraviolet light (UV) and X-rays. UV causes sunburn, and X-rays, while they are important in medicine, exposure to which should be kept to a minimum. Also, gamma rays, which come from nuclear reactions and radioactive decay are high in frequency and are part of the harmful high-energy radiation of radioactive materials and nuclear weapons. The primary effect of high electromagnetic fields is heating of body tissues. Short-term exposure to very high levels of this can be harmful to health.
The 2nd and 3rd answers are incorrect because despite extensive research, there is no evidence that exposure to low level electromagnetic fields is harmful to human health.
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