Which of the following is a function of the placenta?

The correct answer is B. The placenta serves as a crucial organ during pregnancy, facilitating the exchange of gases (oxygen and carbon dioxide) and nutrients (such as glucose and amino acids) between the mother and the developing fetus. This exchange is vital for the fetus's growth and development. Choices A, C, and D are incorrect. The placenta does not secrete insulin; insulin is produced by the pancreas. While the placenta provides some immune support to the fetus, its main role is not immunological protection. Additionally, storing fat-soluble vitamins is not a primary function of the placenta.