Question

sheri often has colds. which behavior can sheri include in her life to boost her immune system?
quitting smoking
avoiding the sun
drinking more orange soda
sleeping less each night

Explanation:

吸烟会损害免疫系统，戒烟有助于增强免疫系统功能。避免阳光（可能缺乏维生素D等影响免疫）、多喝橙汁汽水（高糖等不利健康）、每晚睡眠更少（睡眠不足影响免疫）都不利于免疫系统。

Answer:

quitting smoking