The practice of science can answer only scientific questions. And scientific questions guide the design of investigations. What must be true of the
possible answers to a scientific question?
A. They support an established scientific theory.
B. They do not require the use of physical measurements.
C. They could be shown to be false by evidence.
D. They are at odds with established scientific theories.

How does the image distance (di) of a convex lens compare with the image distance of a concave lens? a. the image distance of the convex lens is positive, and that of the concave lens is negative. b. both are negative for a virtual image. c. both are positive for a virtual image d. the image distance of the convex lens is negative, and that of the concave lens is positive.

Why is rain likely when warm, moisture-laden air meets cold air? a) the lighter warm air will rise and cool down, causing condensation and rain. b) the cold air moves faster and pushes the warm air away, causing condensation and rain. c) the moisture in the warm air condenses on contact with the cold air, causing rain to fall. d) the cold air mixes with the warm air, reducing its temperature causing moisture to condense.

If two parallel light rays hit a mirror, they will not be parallel to each other after they reflect.