A single part of the body can withstand doses of ionizing radiation higher than _____ without death necessarily resulting.

The correct answer is based on understanding the tolerance levels of human tissue to ionizing radiation. The threshold for acute radiation effects leading to serious health consequences generally starts around 1 Gy. However, specific tissues can tolerate higher doses before fatal outcomes are likely.

When looking at the options, 50 Gy is significantly higher than the lethal dose for most human tissues, which means some body parts can endure quite high levels of radiation with less risk of immediate mortality. For example, the bone marrow and gastrointestinal tract are among the most sensitive tissues and can be severely affected by much lower doses. In contrast, certain tissues may be more resilient and may withstand higher levels of radiation.

The data indicates that doses above 5 Gy can lead to serious and potentially fatal health effects in humans, specifically impacting critical systems like the hematopoietic and gastrointestinal systems. Therefore, suggesting that a part of the body can handle up to 50 Gy without leading to death aligns with current radiation tolerance research and the understanding of human tissue response.

Other options, such as 0.5 Gy, 500 Gy, and 5 Gy, do not accurately reflect the higher tolerance of tissues, with 500 Gy being excessively high and beyond any realistic tolerance levels for human tissues.