In developed countries, the birth and death rate are low, whilst in developing countries, both the rates are high. Developed countries usually are more industrialized and have higher per capita income levels, whereas developing countries, are less industrialized and have lower per capita income levels.
The main factors affecting birth are:
Age.
Health.
Heredity.
Ovulation cycle.
Location.
Miscarriage
The answer is Digestive system :)
