1 Sheila and Kevin are helping their science teacher design a lab exercise about gravity in the universe. The simple set-up requires the use of two softballs. Ball 1 has nothing attached to it. Ball 2 has a long string connected to it The first step of the activity is to throw Ball 1 in a straight line down the hallway to model a planet that is not affected by the Sun's gravity. What should be done in Step 2 to model the Sun's effect on a planet? A The ball is thrown around the body while holding on to the string.
B The ball is thrown around the body with the string trailing behind.
C The ball is thrown in a straight line while holding the string
D The ball is thrown in a straight line with the string trailing behind.

The allotropes of carbon include a variety of structures that include three-dimensional tetrahedral lattices, planes of hexagonal rings, cylindrical tubes of hexagonal rings, and spheres of five- and six-membered rings. similar shapes of network covalent atomic solids are possible with carbon nitride, boron, and pure silicon (e.g., silicene is a graphene-like allotrope of pure silicon). in contrast, silicates exist as either highly ordered or amorphous (more random) three-dimensional lattices. what could explain why there are there no naturally occurring sheets, stacked sheets, cylindrical tubes, or spheres of network covalent atomic solids composed of silicon and oxygen (sio2)? would pure silicate structures make good lubricants or good electrical conductors?