Benchmark 4G
The Physical Setting: Forces of Nature
Grades K-2, page 94

Things near the earth fall to the ground unless something holds them up.

The most closely related standard is at a higher level of sophistication.

NSES Content Standard D 
Earth and Space Science: Earth in the Solar System 
Grades 5-8, page 161 
Gravity is the force that keeps planets in orbit around the sun and governs the rest of the motion in the solar system. Gravity alone holds us to the earth's surface and explains the phenomena of the tides.