Which of these is NOT a metamorphic rock?

Basalt
Slate
Marble​

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.

Multiply or divide to make this english distance conversion. 174 inches = feet (14.5, 58, 2,088, 23)

Which of the following is another term for a planned economy