The Dark, Seasonal Markings on Mars That Grow in the Spring

Multiple Choice

The dark, seasonal markings on Mars that grow in the spring and fade in the autumn are believed to result from:

A) microbial activity in the soil (or regolith) .
B) lighting effects that vary as the angle of the Sun changes with the seasons.
C) dust being blown by winds, alternately covering and uncovering dark rocks.
D) plant life.