Final answer:
Smoking cigarettes over a long period of time and smoking a large number of cigarettes each day are factors that increase the risk of lung cancer. Starting to smoke again after a period of not smoking can also increase the risk.
Step-by-step explanation:
Smoking cigarettes over a long period of time and smoking a large number of cigarettes each day are both factors that increase a person's chance of developing lung cancer. This is because cigarettes contain harmful substances that can damage the lungs and lead to the development of cancerous cells. Not smoking for a year and then starting to smoke again can also increase the risk as it exposes the lungs to toxins once more.
Learn more about factors increasing the risk of lung cancer