Final answer:
The leading cause of cancer death for both men and women in North America is lung cancer, primarily due to late diagnosis and its association with tobacco smoke exposure.
Step-by-step explanation:
The leading cause of cancer death for both men and women in North America is lung cancer. Lung cancer accounts for approximately 31% of all cancer deaths in males and 27% in females, which is higher than other cancers like breast, colorectal, and prostate cancer. The high mortality rate can be attributed to lung cancer often being diagnosed at a later stage, which makes it more difficult to treat. The predominant cause of lung cancer is exposure to tobacco smoke, with smoking being responsible for about 90% of lung cancer fatalities. Other risk factors include secondhand smoke, exposure to certain toxins, and genetic predispositions.