However, we now know that since oxygen levels were much lower in the Mesozoic than we assumed, there was much less plant life for sauropods to eat than we thought.

然而我们现在知道了，由于中生代空气的含氧量比我们想象的要低得多，所以蜥脚类动物可食用的植物也比我们想象的要少得多。