There are places in America and other parts of the world where herds of wild horses live, well-adapted to the environment. If mules are so much better adapted to harsh environments than either horses or donkeys, why have there never been populations of wild mules?
A.
because mules are domesticated animals
B.
because mules cannot reproduce
C.
because mules are not natural
D.
all of these

Imagine that a new planet is discovered with two moons of equal mass: moon a and moon b. the mass of the new planet is greater than the combined mass of its moons. moon a is farther away from the new planet than moon b. what is the planet's gravitational pull on moon a compared to the planet's gravitational pull on moon b? the planet's gravity repels moon a with a greater force than it repels moon b, which is why moon a is farther away. the gravitational pull on moon b is greater than on moon a because moon b is closer to the new planet than moon a. the gravitational pull on moon b is greater than on moon a because moon b is farther away from the new planet than moon a. the gravitational pull on moon a is the same as the gravitational pull on moon b because distance does not affect the planet's gravity.