Final answer:
Dickkopf dkk1 is a Wnt antagonist that inhibits the Wnt signaling pathway by preventing the interaction of Wnt ligands with receptors.
Step-by-step explanation:
Dickkopf dkk1 is a Wnt antagonist. The Wnt signaling pathway plays a crucial role in animal development by regulating various processes such as cell proliferation and differentiation. Wnt antagonists like dickkopf dkk1 bind to Wnt ligands and prevent their interaction with receptors, thus inhibiting the Wnt signaling pathway. This inhibition leads to changes in gene expression and cellular responses.