【正确答案】 D

【答案解析】hazard和danger意思相近：危险：危害。There is a widespread danger of disease in this area．在这个地区疾病有扩散的危险。protection：保护；防护。Insurance is a protection against unforeseeable misfortunes．保险是对不可预见的灾难的一种防护措施。indication：指示：迹象。Indications of a possible earthquake have been observed．人们观察到一些可能要地震的迹象。immunity：免疫力。Scientists are studying why some individuals have natural immunity to the disease．科学家们在研究为什么一些人对这种病有自然的免疫力。