The fish species Astyanax mexicanus includes blind, cave-inhabiting populations whose eyes degenerate during embryonic development. To understand how eye degeneration worked, Yamamoto and Jeffery (2000) replaced the lens of the degenerate eye on one side (randomly chosen) of a blind cave fish embryo with a lens from the embryo of a “normal,” sighted fish. This procedure was repeated on all individuals in a sample of blind cave fish. Final eye size was measured on both sides of each experimental fish, after embryonic development was complete. Remarkably, a normalized eye was restored on the transplant eyes of blind cave fish but not on the unmanipulated side. Based on the preceding description of a laboratory experiment, identify which of the six main strategies of experimental design (listed in Section 14.2) were incorporated.