(单选题)

If photosynthetic humans had pores, what would be the disadvantage?

A.They would absorb too much CO2.

B.They would release some useful substances.

C.They would be too small for human beings.

D.They would keep gases from entering the human body.

参考答案：B

参考解析：

细节理解题。根据文章第五段第三句“If photosynthetic humans had chloroplasts (叶绿体), they might need porous skin to let in carbon dioxide, but such pores might let other things leak in or out — for instance, moisture (水分) —in ways that might prove harmful to the human body.”可知，如果光合作用的人类有叶绿体，他们可能需要多孔的皮肤来吸收二氧化碳，但这样的毛孔可能会让其他东西渗入或渗出，比如水分，那这样是对人体有害的。因此，如果光合作用的人类有毛孔，就会释放出一些有用的物质。故选B。

知识点：阅读理解四选一英语专业基础知识阅读理解教师招聘-小学英语