Lack of artifacts from the prehistoric period can be overcome in the study of art history by virtue of
a. assertions made by ancient historians
b. common features shared by all works of art
c. comparisons with other prehistoric works
d. reliance upon available written records

changeable lenses of different focal lengths allows light to enter the camera,which then forms the image on light-sensitive film;

the sculpture i am pretty sure you are talking about is the statue b. the david statue now lives in the galleria dell'accademia, florence, italy. it was made by ‎michelangelo.