On a hot summer day a student left a ice cube outside and it melted it this radiation combustion conduction or convection

The answer to your question is conduction.

Stimulants speed up the central nervous system.

Answer in 2009 barack obama signed into law the family smoking prevention and tobacco control act, the new law (h.r.   1256) represents the most sweeping action taken to date to reduce what remains the leading preventable cause of death in the united states;