Answer:
B. Gravity held the pieces of forming planets together.
c. Gravity pulled most of the matter into the center of the solar system
D. Gravity caused the planets and Sun to have spherical shapes.
Explanation:
When a collection of grains pulled together by their gravitational forces would keep in by the gravity of a star, it would eventually became bigger to the point a planet was formed.
The sun's strong gravitational force pulled most of the matter around it to the center of the solar system.
The spherical shape of planets is a result of their gravity pulling equally from all sides, shaping it into a sphere.
Answer:

Explanation:
<u>Synthesis reaction:</u>
In the synthesis reaction, two reactants combined to form a single product.
For example,
"A" and "B" are two reactants then combined to form a "AB" product.
The chemical reaction is as follows.

The product "MgO" is formed by magnesium reacts with oxygen to form Magnesium oxide.
The chemical reaction is as follows.

comets, astroids oort clouds which surround the kuiper belt
Answer:
C
Explanation:
Potassium metal reacts very rapidly with water, which forms Potassium hydroxide (KOH) and hydrogen gas (H2).
The complete question is found on the image attached.
Answer:
a) Rb= +1, Br= -1
b)Bromide and rubidium ions are related to krypton
c) C
Explanation:
Rubidium is found in group 1 with a charge of +1. Bromine is found in group 17 with a charge of -1. Both species have the same configuration as krypton. The ionic sizes of the ions are a very similar to each other Rb+ is 166 while Be is 167.
This RbBr is an ionic compound.