Exposure to 300 rad is likely to result in which effect?

Exposure to 300 rad is within the range that can cause temporary epilation, which is the loss of hair that might occur after exposure to significant doses of radiation. Temporary epilation is generally result from doses in the range of 200 to 1000 rad, where hair follicles are damaged, but recovery is possible once the exposure ceases and skin regenerates.

In contrast, permanent epilation would typically require exposure to higher doses, likely above 1000 rad, where the hair follicles are permanently destroyed, and regrowth is not expected. Suppressed menstruation usually occurs at lower doses and can be influenced by a variety of factors, but is not as directly tied to high radiation exposure as temporary epilation. Gastrointestinal syndrome is associated with even higher levels of radiation exposure (around 600 rad or more), leading to severe damage to the intestinal lining and other critical tissues, presenting as more acute symptoms.

Thus, at a dose of 300 rad, the expected effect aligns more closely with temporary epilation, as it is significant yet not exceedingly high.