[解析]
(1)C.细节理解题。根据第一段的最后一句While there,he found that people did not suffer from heart attacks,diabetes (糖尿病),being overweight and many other diseases common in western countries. (在那里,他发现那里的人没有心脏病发作、糖尿病、体重超重或许多其他西方国家常见的疾病)可知,基塔瓦人没有西方国家常见的疾病。故选C项。
(2)D.细节理解题。根据第三段的第一句At the end of three months,the group following the Mediterranean diet had reduced their blood sugar levels by a small amount but those following the Stone Age diet had much lower levels of sugar in their blood. (三个月后,遵循地中海饮食习惯的小组血糖水平略有下降,但遵循石器时代饮食习惯的小组血糖水平要低得多)可知,遵循石器时代饮食习惯的人血糖水平低。故选D项。
(3)B.细节理解题。根据第四段的最后一句中的The diet contains some meat,fish,vegetables and nuts (坚果) but it doesn't contain any dairy products (乳制品) or grains,and there is no salt. (这种饮食包括一些肉、鱼、蔬菜和坚果,但不含任何乳制品或谷物,也不含盐)可知,石器时代的饮食中没有盐。故选B项。
(4)C.推理判断题。根据最后一段的第四句Because of their poor health care,there is more chance of them dying at a young age. (由于他们的卫生保健水平落后,他们年轻时死亡的可能性更大)可知,基塔瓦人寿命不长的原因在于卫生保健条件不好。故选C项。