In classical ( Ricardian ) economics, the theory of production and the theory of growth are based on the theory or law of variable proportions, whereby increasing either of the factors of production (labor or capital), while holding the other constant and assuming no technological change, will increase output, but at a diminishing rate that eventually will approach zero. These concepts have their origins in Thomas Malthus ’s theorizing about agriculture. Malthus’s examples included the number of seeds harvested relative to the number of seeds planted (capital) on a plot of land and the size of the harvest from a plot of land versus the number of workers employed.  See: Diminishing returns
Babies grow at a very fast rate in the first year of life as well as into their toddler years. Concern about the growth and development of your baby is a natural part of being a parent. Visits to the pediatrician will give you a sense of how your baby is developing. This will tell you how your baby is growing in comparison to other babies of the same age and sex. But you may want to check your baby’s growth in between pediatrician visits. By checking your baby’s vital statistics and comparing these measurements to growth and milestone charts, you can measure your baby’s growth.