Over evolutionary 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

No need for that part in the body.

Explanation:

The loss of various parts by the organisms occurs due to natural selection because there is no need for that organ for the organism which allows them to remove and survive without that organ. Whales have lost their hind limbs because there is no need for it in swimming so it becomes useless and with the passage of million of years these legs are disappeared from whale's body so we can conclude that natural selection is the main cause for these losses in organisms.

explanation:

the universal gravitation equation. since the gravitational force is directly proportional to the mass of both interacting objects, more massive objects will attract each other with a greater gravitational force. if the mass of one of the objects is doubled, then the force of gravity between them is doubled.