It can be inferred from the passage that ______.

参考解析：

推理判断题。根据第一段第二句“Every day entire species of plants and animals die out”可知，每天都有物种在灭绝，说明物种比以前少了，所以A项错误。根据第二段对The Diversity of Life的简介“states in a matter-of-fact way what is known about the Earths past and the impact of mankind on its plant and animal life. Meanwhile, he suggests solutions for the present crisis.”可知，这本书陈述了地球的过去、人类对动植物的影响、以及现存危及的解决方法，并没有描述所有动植物，所以B项错误。根据第一段第三句、四句“We already know about five mass extinctions, and now a sixth seems to be underway. This one is different because it is man-made.”可知，前五次大灭绝不是人类引起的，所以C项错误。根据第一段倒数第二句“Often they die out before we ever know they existed.”可知，很多物种在我们知道它们存在之前就灭绝了，所以D项正确。故选D。