Process of science: explaining apparent retrograde motion part a at most times, mars appears to move relative to the stars. the exceptions are during its periods of apparent retrograde motion, when mars appears to move relative to the stars. check two responses below, one for each of the two blanks in the question. blank 1) to the right (westward) (blank 1) to the left (eastward) (blank 1) fast (blank 1) slow (blank 2) to the right (westward) (blank 2) to the left (eastward) (blank 2) fast (blank 2) slow