Final answer:
The items that can cause cancer are exposure to toxins and smoking, both of which involve carcinogens that can lead to mutations causing cancer. Smoking is a significant risk factor for various types of cancer, while exercising actually reduces cancer risk.
Step-by-step explanation:
The items that can cause people to develop cancer are exposure to toxins and smoking. Exposure to various carcinogens, which include certain chemicals such as those found in tobacco smoke, can lead to the mutations that cause cancer. Among the chemicals in tobacco smoke, nicotine and several others have been shown to be cancer-causing. This exposure makes smoking a significant risk factor for cancers of the lung, mouth, throat, and bladder. In contrast, exercising is generally associated with reduced cancer risk and is not a carcinogenic factor. Heart disease and diabetes, while serious health conditions, are not direct causes of cancer.