they're light
they're strong
both of these
Correct!
Gazelles have delicate but sturdy legs. Their legs are light because they only have muscles at the top. Their strong hind limbs and rump muscles help propel the gazelle forward when it runs.
Thomson's gazelle
On the dry grasslands of eastern Africa, the Thomson's gazelle grazes in the tall grass. Suddenly, it hears a noise and raises it head. The gazelle is completely still until it notices a lion. In a flash, it bounds into the air and is off and running. The lion charges after it, but the slim, graceful gazelle is too fast and outruns the fierce predator.