Final answer:
The allele that causes death of an organism when exposed to a specific temperature range is a dominant lethal allele. This is because it results in death whether one or two copies of the allele are present.
Step-by-step explanation:
The allele you are describing is known as a lethal allele. Lethal alleles can be either dominant or recessive. However, in the context of the question where the allele causes death only upon exposure to a specific temperature range, this sounds like a conditional form of a lethal allele. When considering the inheritance pattern described in the question, where the allele causes death when the organism is exposed to a particular temperature, irrespective of whether it's found in the homozygous or heterozygous state, it is most appropriately categorized as a dominant lethal allele.
An example of a dominant lethal allele in humans is Huntington's disease, where individuals with one copy of the mutated allele will develop the disease. Similarly, a temperature-sensitive allele that causes death at certain temperatures would also be dominant because it leads to death regardless of whether the individual has one or two copies of the allele.