题目选项分析

The retinas of premature babies are not fully developed at birth. Because their retinas are so delicate, premature babies sometimes lose their sight. Methods for preventing this syndrome, which is called retinopathy of prematurity, have improved, but the proportion of premature babies who lose their sight because of this syndrome has increased.

Which of the following, if true, best reconciles the apparent discrepancy described above?

【选项】The oxygen that must be administered to premature babies at birth can sometimes have a damaging effect on the babies' retinas, but the oxygen is now administered in less damaging concentrations than it used to be.