German Shepherd dogs are bred together to produce desired physical and behavioral characteristics. Today they are bred to have a sloping back and high intelligence. The pictures show drawings of a German Shepherd dog in the 1900's and a German Shepherd dog today.
German Shepherd Dog in 1909 German Shepherd Dog Today
Which best describes how the sloping back of the German Shepherd dog has changed so dramatically over the past century?
A
Humans bred the German Shepherd dogs with the most sloped backs until this desired trait was achieved.
B
Humans let the German Shepherd dogs choose their mates, and the sloping back trait eventually appeared.
C
Humans bred the German Shepherd dogs with the straightest backs to offset the sloping backs, but it did not work.
D
Humans accidentally bred one German Shepherd dog with a sloped back and this changed the appearance of the breed as a whole.