I need help with science pls help me!

Adilute aqueous potassium nitrate solution is

Why is retrograde motion an apparent motion

Observation and experimentation have led many scientists to accept a theory about the origin of the universe. this theory is called the big bang theory. scientific evidence collected and observed by scientists around the world suggests that the universe is ever expanding from a hot and dense initial state. what makes this a scientific theory? (2 points)