Which of the following observations is an example of a positive correlation? Multiple Choice O When women gain less weight than average during pregnancy, the birthweights of their babies tend to be lower than average O When a group of children increases their physical activity levels, the percentage of the children who contract cold infections decreases. O When members of a population consume fewer fruits and vegetables, their risk of high blood pressure increases. O When a population's intake of green tea increases, the percentage of lung cancer cases in that population decreases