Final answer:
The feature of Watson and Crick's model that suggests a mechanism for genetic information copying is semi-conservative replication.
Step-by-step explanation:
The feature of Watson and Crick's model that most directly suggests a mechanism by which genetic information is copied within cells is the concept of semi-conservative replication.
In the double-helix model proposed by Watson and Crick, the two strands of DNA separate during replication, and each strand serves as a template for the synthesis of a new complementary strand.
Thus, during replication, one strand of the original DNA molecule remains intact, while a new strand is synthesized using the existing strand as a template. This process ensures that the genetic information is faithfully copied and passed on to daughter cells.