1. A B. Theory is a framework of ideas and assumptions that has been well tested and can be used to explain some set of observations and make predictions about the world.
Although "theory" is a concept that is always in discussion, the scientifics agree on some points. It must be logically composed of concepts, definitions, assumptions, and generalizations. Secondly, it's major function is to describe and explain, it is important to say that a theory is a general explanation that leads to basic principles. In the third place, a theory is heuristic because it stimulates and guides to further development of knowledge.
2. How can astronomers locate objects in the sky?
D. by using the celestial sphere and constellations
Astronomers locate objects in the sky in a very simillar way we locate places in a map. Instead of using latitude and longitude, they use declination and right ascension. This is based on the celestial sphere, an imaginary object that is created by asuming all objects in space are at the same distance. By doing this astronomers can determine a line of zero latitude and zero longitude and therefore locate precisely distant objects. They can use also constelations as references with this same method.