Ore deposits

a. are distributed uniformly throughout the earth's crust
b. are rock units that have a significant concentration of metals
c. are minerals that contain a high amount of lead (pb)
d. have diffuse metal ions bonded to nonmetallic elements in a variety of minerals

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)