单选题 What does the comment "This is logical." in line 5 of the first paragraph (underlined) mean?

A、 There is no clear way to determine the extent of our ancestor's knowledge of plants.
B、 It is not surprising that early humans had a detailed knowledge of plants.
C、 It is reasonable to assume that our ancestors behaved very much like people in preindustrial societies.
D、 Human knowledge of plants is well organized and very detailed.

【正确答案】 B

【答案解析】[解析] 本题考查细节。在这句评论的前面，作者曾讲到过，早期的人类对植物有着广博的知识，虽然今天我们不可能知道我们的祖先对植物都了解些什么，但可以断定他们掌握了非常详细的植物学知识。“This is logical．(这很合乎逻辑)”，因为“Plants are the basis of the food pyramid for all living things，even for other plants．(植物对所有生物，甚至对于其他植物来说，是食物金字塔的基础。)”所以，他们掌握了非常详细的植物学知识一点也不令人吃惊，即选项[B]正确。