Final answer:
The number of deaths caused by second-hand smoke out of the 435,000 attributed to tobacco smoking in 2000 is not directly stated, but understanding the severe health risks associated with second-hand smoke is crucial.
Step-by-step explanation:
Regarding the question of how many of the 435,000 deaths attributed to tobacco smoking in 2000 were caused by second-hand smoke, it is critical to highlight that exposure to second-hand smoke carries significant health risks. Second-hand smoke, a mixture of sidestream smoke and the smoke exhaled by the smoker, contains over 7,000 substances, many of which are toxic and carcinogenic. It has been linked to an increase in the risk of lung cancer by up to 30 percent for non-smokers who live with smokers.
Considering this information and the widespread impact of second-hand smoke on human health, the correct answer to the student's question is not directly provided, but knowing the serious health implications, it highlights the importance of understanding and preventing exposure to second-hand smoke.