1. explain the direction of gravity’s pull 2. explain when gravity exists and which objects pull on which 3. be able to explain the scale of the solar system and why there are no correctly drawn models of it using data

1).  The direction of gravity's pull between two objects is on the line between their centers of mass. (That's why the "center of mass" is often called the "center of gravity".)

2).  Gravity always exists, and ALL objects with mass pull on ALL other objects with mass.

3).  I am able.

There are no models of the solar system correctly drawn to scale because the size of the objects (sun, planets, moons) are so tiny compared to the space between them, and the distances between the objects are so huge compared to their size.  

If you tried to draw a model to correct scale, and you drew a couple of objects big enough to SEE on the paper, then you'd almost need a piece of paper the size of Texas to show the whole solar system.

-- Pluto's orbit is 8,565 times the size of the sun.

-- If the Moon is the size of a dime, then ...

the sun is 1/2 mile away

it's 23.5 feet across

Pluto's orbit is 19 miles across

reserve is the answer