Tobacco is injurious to health as it can result in the following complications:
1. Tobacco contains carcinogenic substances, i.e, substances which can cause cancer. Various cancers like oral cancer, lung cancer, etc, have been associated with tobacco.
2. It is a major risk factor for heart diseases, lung disorders like emphysema, strokes, gastric ulcer, bronchitis.
3. It contains addictive drugs like nicotine. It makes the person depend on tobacco psychologically and physically.
4. It may also result in impotency or infertility in individuals.
So, the correct option is 'All of these'.