8. Where is blood produced in infants after birth?
Answer: B
Blood is produced in the red bone marrow of infants after birth.
In infants, blood production primarily occurs in the red bone marrow, which takes over from the liver and spleen that are involved in hematopoiesis during fetal development.
A) Heart chamber
The heart chamber is responsible for pumping blood but is not involved in the production of blood cells. Therefore, this option is incorrect as it does not serve the function of hematopoiesis.
B) Red bone marrow
Red bone marrow is the main site for blood production in infants after birth. It contains hematopoietic stem cells that differentiate into various types of blood cells, making this option the correct answer.
C) Liver
While the liver plays a role in blood formation during fetal development, its role diminishes significantly after birth. Thus, it is not the primary site of blood production in infants, making this option incorrect.
D) Spleen
The spleen can produce blood cells, but its role is also significantly reduced after birth. It is not the main site for blood production in infants, which makes this option incorrect.
Conclusion
The red bone marrow is definitively the primary site of blood production in infants after birth, while the heart, liver, and spleen do not fulfill this role to the same extent. This is why option B is the correct answer, as it accurately reflects the physiological changes that occur in hematopoiesis postnatally.