Cane toads are large, poisonous frogs native to Central and South America. They were introduced in Australia in 1935 in an attempt to control the beetle population in the sugarcane fields. Since then, their speed has increased significantly. According to recent studies, scientists have determined that they now have longer legs, are more active, and are larger in size than their ancestors in Central and South America. Which statement best explains why the cane toads in Australia move more quickly than their ancestors?