Final answer:
Cancer cells can be guided by molecular gradients to healthy organs through the process of chemotaxis, which is crucial for metastasis.
Step-by-step explanation:
The concept of chemotaxis pertains to the directional movement of a cell in response to a chemical attractant. Considering this, the answer to whether cancer cells can be recruited to healthy organs through self-directed chemotaxis is 'a. Yes, molecular gradients guide cancer cells.' Just as leukocytes move in response to chemical signals, cancer cells can utilize chemotaxis to migrate towards organs, a process that is fundamental to the metastasis of cancer. It includes the movement of cancer cells from the primary site to distant sites within the body. Hence, chemotaxis is integral to how metastatic cancer cells find and colonize new sites in the body.