What 2 planets can be seen from earth?
Mercury, Venus, Mars and Saturn can be seen with the naked eye.
The constellations of the zodiac fall on the plane of the ecliptic (the plane in which the Earth orbits the Sun) and all the Sun's planets orbit also in the plane of the ecliptic. This means that ALL the planets eventually move through ALL the zodiacal constellations (as seen from Earth). It also therefore follows that the planets are never seen in the non zodiacal constellations.