of brain and other organs and systems. Socio-economic Status Socio-economic factors definitely have some effect. It has been seen that children from different socio-economic background vary in average body size at all ages. The families with high income are primarily more advanced.
The most important reasons behind this are better nutrition, better facilities, regular meals, sleep, and exercise. Family size also influences the growth rate, as in big families with limited income, sometimes children do not get the proper nutrition and hence the growth is affected.