Final answer:
The combining form 'onco-' comes from the Greek 'onkos' which means mass or tumor, and is used in medical terminology to refer to cancer-related topics.
Step-by-step explanation:
The combining form of 'onco' is 'onc/o', derived from the Greek word ονκος (onkos), meaning mass or bulk, particularly relating to a tumor. In medical terminology, 'onc/o' is used as a prefix to create words that pertain to tumors or cancer. For example, 'oncology' is the field of medicine that specializes in the study of tumors and cancer.
As for the root word, 'onco' itself is the root, reflecting the original Greek term, which has been adopted into the medical lexicon to refer to growths or masses, commonly understood as tumors in the context of cancer. Basic science questions a researcher might ask about cancer could include:
"What are the molecular mechanisms that lead to cell transformation into cancerous cells?" An applied science question on the same topic might be: "Which novel compounds can be developed to target and inhibit the growth of specific types of tumors?"