Fluid surrounding the fetus in the uterus

Steps:

• Examine the diagram of the developing fetus, noting the sac enclosing it.
• Recall that the fetus develops inside the amniotic sac within the uterus.
• Identify the liquid filling this sac as the protective medium for the fetus.
• Confirm the liquid at x matches the description of amniotic fluid.

Why A is correct:

• Amniotic fluid is defined as the clear, watery liquid that fills the amniotic sac, cushioning and regulating temperature for the fetus.

Why the others are wrong:

• B: Blood circulates within the fetus or mother's vessels, not as the surrounding liquid.
• C: Urine is produced by the fetal kidneys and contributes to amniotic fluid but is not the primary liquid.
• D: Water is a component of amniotic fluid but lacks the specific protective and compositional role.

Final answer: A