Formation of BMP-4 Gradient in Frog Embryos
Which of the following contribute to the formation of the BMP-4 concentration gradient in the frog embryo?
A. BMP-4 is produced in the ventral portion of the embryo.
B. Chordin is produced in the Spemann organizer.
C. Chordin inhibits BMP-4.
D. Xolloid is produced in the ventral portion of the embryo.
E. Xolloid degrades chordin.
AA only
BA, B, and D only
CA, B, and C only
DA, B, C, D, and E
EA, C, and E only