<prompt> In WHO Road to health card the upper reference line represents:80th percentile for boys50th percentile for girls80th percentile for girls50th percentile for boys  <response>: 50th percentile for boys. The Indian growth cha is having 4 reference curves. The topmost curve corresponds to 80 of the median of the WHO reference standard. The lower lines represent 70 , 60 , 50 of that standard. WHO growth cha is having 2 reference curves. The upper reference curve represent the median 50 percentile for boys and the lower reference curve the 3 percentile for girls. The space between the two growth curves is called as road to health. This will include the zone of normality. 