Assuming all other properties remain constant, which of the following changes made to an enclosed container of gas will INCREASE the density? A.
Decreasing the volume of the container

B.
Applying heat to the container

C.
Reducing the temperature of the container

D.
Reducing the pressure on the container

look at this it will give you up to 17 answers  

the statements that apply here about binary star system are

"have stars that might appear to wobble"

"often have one star that is brighter than other"

a binary star is a star system consisting of two stars revolving around their common barycenter. systems of two or more stars are called multiple star systems.