The moon, mars, and earth all have plate tectonic movement, however, they all are active in different ways. The earth probably has the most tectonically advanced system. Tectonic plates are any one of the internally rigid crustal blocks of the lithosphere that move horizontally across the earth's surface relative to one another (Answers.com).
Mars has a magnetic field in which move its plates about its surface. The magnetic stripes push and pull the plates causing tectonic movement. One scientist says that the more measurements they collect the more accurate they are (geology.com). The scientists have found many similarities of the effects of the magnetic fields affecting the planets crusts between Earth and Mars. The fact that the plates are able to move on mars suggest that it too, like Earth must have some kind of liquid make up in the core in order for the plates to move and be molded.
The Moon is a little bit more complicated. The things such as meteors, meteoroids, and meteorites hit the Moon’s surface causing an impact strong enough to affect and move the tectonic plates of the Moon. In addition, volcanic eruptions can also cause the plates to move on the Moon. When craters are formed from the space debris such as meteors, the craters are big enough to move the plates and Moon’s crust. Sources:
moon: http://geophysics.suite101.com/article.cfm/why_earth_has_fewer_craters_than_moon mars: http://geology.com/nasa/mars-plate-tectonics.shtml
definition of plate tectonics: http://www.answers.com/topic/tectonic-plate