Answer to Question 1
1, 2, 4
Explanation: 1. Closure of the foramen ovale is a function of changing arterial pressures.
2. Closure of the ductus venosus is related to mechanical pressure changes that result from severing the cord, redistribution of blood, and cardiac output.
4. Increased systemic vascular resistance and decreased pulmonary vascular resistance; with the loss of the low-resistance placenta, systemic vascular resistance increases, resulting in greater systemic pressure. The combination of vasodilation and increased pulmonary blood flow decreases pulmonary vascular resistance.
Answer to Question 2
1,3,4
Rationale 1: Fetal growth occurs by an increase in cell numbers in one stage.
Rationale 2: Growth of the fetus occurs steadily over time.
Rationale 3: Fetal growth occurs by an increase in cell size and number during one stage.
Rationale 4: Fetal growth occurs by an increase in cell size alone during one stage.
Rationale 5: A balanced diet is needed to ensure proper fetal development, so all nutrients are needed, not just vitamins and minerals.