Erosion: While water, and wind are the primary forces of Erosion on the Earth, this meteoric rain is the only real erosive agent on the moon.
(water, and wind; are; the primary forces of Erosion on the Earth) (this meteoric rain; is; the only real erosive agent on the moon)
water, and wind this meteoric rain
are is
the primary forces of Erosion on the Earth
the only real erosive agent on the moon