Given a scientific question and its correct answer, generate supporting facts for the answer. This supporting fact can be an explanation for the answer to the given question.

Input: Consider Input: Question: Cigarettes are a major source of what kind of chemical substances linked with cancer? Answer: carcinogens

Output: Courtesy of the CDC/Debora Cartagena. Cigarettes are a major source of chemical carcinogens .

Input: Consider Input: Question: Electrons in the "outer shell" are also known as what kind of electrons? Answer: valence

Output: Determine the total number of valence (outer shell) electrons. For cations, subtract one electron for each.

Input: Consider Input: Question: In vascular plants, what two basic structures are made of dermal, vascular, and ground tissues? Answer: roots and stems
Output: Like roots, the stems of vascular plants are made of dermal, vascular, and ground tissues.