Fun facts for the precambrian era this goes under science

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)

What are several ways to reduce the effect of friction

Ireally need ! calcium metal reacts with a potassium chloride solution to form calcium chloride and potassium ions. balance this reaction. (s) + (aq) → cacl2(s) + +(aq) a) 1, 2, 1, 2 b) 1, 2, 1, 1 c) 1, 1, 1, 1 d) 2, 1, 2, 1