Which best examples why a wood-burning fireplace represents an open system.
a. because the ashes have to be swept away
b. because a fire requires oxygen from the atmosphere to burn
c. because they can be used for cooking
d. because they are not all made out of brick

answer///multiple alleles;

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.