Assertion: platypus's foot | /r/HasProperty | back
Facets:
Source sentences:
text: Platypuses swim with their front feet and steer with their tails and back feet.
text: Platypuses swim with their front feet, with a rowing motion, and move back or turn with their back feet and tails, which they use to steer.
text: When swimming, the platypus moves itself with its front feet and uses its back feet for steering and as brakes.