Which statement is true?

the earth's moon is thought to have formed when a mars-sized planet collided with earth during its final stages of planetary accretion.
without the earth's moon, life on earth would not be possible.
the earth's moon is the smallest moon relative to its host planet.
the earth's moon is the same size as the earth.

If 1 lb of fat is stored by the body for each 14.6×103kj of excess nutritional energy consumed, how long will it take this person to gain 1 lb?

Ateam of astronauts is on a mission to land on and explore a large asteroid. in addition to collecting samples and performing experiments, one of their tasks is to demonstrate the concept of the escape speed by throwing rocks straight up at various initial speeds. with what minimum initial speed vesc will the rocks need to be thrown in order for them never to "fall" back to the asteroid? assume that the asteroid is approximately spherical, with an average density p 3.84 x108 g/m3 and volume v 2.17 x 1012 m3 recall that the universal gravitational constant is g 6.67 x 10-11 n m2/kg2

Protons and neutrons are found within the nucleus of an atom