Near the earth's surface, vertical changes of air density with height are caused primarily by
A) vertical moisture gradients.
B) horizontal moisture gradients.
C) horizontal temperature gradients.
D) vertical temperature gradients.
Question 2
An inferior mirage
A) is made of a single degraded image.
B) is made of 2 images, both imaginary.
C) is made of 2 images, one a true image and one an inverted one.
D) is made of 3 images, one a true image and the two others are degraded replicas of the original.