Over long periods of time, many cave-dwelling organisms have lost their eyes. tapeworms have lost their digestive systems. whales have lost their hind limbs. how can natural selection account for these losses?

natural selection cannot account for losses, but accounts only for new structures and functions.

under particular circumstances that persisted for long periods, each of these structures presented greater costs than benefits.

natural selection accounts for these losses by the principle of use and disuse.

the ancestors of these organisms experienced harmful mutations that forced them to lose these structures.