Which of the following asteroids approach but do not cross Earth's orbit?

The Amors are a group of asteroids that approach Earth's orbit but do not cross it. They have orbits that bring them close to Earth, typically at a distance within the range of Earth's orbit, but their paths are such that they stay outside of Earth's orbital path around the Sun. This characteristic is important for understanding their potential impact risk and the dynamics of near-Earth objects.

In contrast, the Apollos are a class of asteroids that not only approach Earth's orbit but actually cross it, which means they have the potential to come into collision with Earth. The Atens are similar in that they have orbits which also intersect with Earth's path, being primarily inside Earth's orbit. The Centaurs, on the other hand, are not classified as near-Earth asteroids and have orbits that typically lie between those of the inner and outer planets.

Thus, the Amors represent a specific and important category of near-Earth objects that could be monitored for close approaches without the immediate concern of crossing into Earth's orbital path.