Final answer:
Poor nutrition, infectious diseases, and hereditary disorders can adversely affect the development and functioning of the immune system in children.
Step-by-step explanation:
The most important factor adversely affecting the development and functioning of the immune system in children is poor nutrition. Proper nutrition is crucial for the immune system's growth and functioning. A lack of essential nutrients can weaken the immune system, making children more susceptible to infections and diseases.
Infectious diseases are another factor that can adversely affect the immune system in children. When children frequently get sick due to infections, their immune system is constantly fighting off pathogens, which can put a strain on it and impact its development.
While hereditary disorders can affect the immune system, they are not as common as poor nutrition and infectious diseases.
Stress can also have negative effects on the immune system, but its impact on children's immune system development is not considered as significant as poor nutrition and infectious diseases.
Learn more about Factors affecting the development of the immune system in children