Ultrasound Imaging Uses Echoes

Steps:

• Ultrasound scanner emits high-frequency sound waves into the body.
• Waves travel through tissues and encounter the baby.
• Some waves bounce back as echoes from the baby's surfaces.
• Scanner detects and processes these echoes to construct the image.

Why C is correct:

• Ultrasound imaging forms pictures using reflected sound waves, following the echo principle where time and intensity of returning echoes map tissue boundaries.

Why the others are wrong:

• A: Absorbed ultrasound reduces signal strength but provides no echo data for imaging.
• B: The baby does not emit ultrasound; the scanner generates it.
• D: Refracted ultrasound bends waves at interfaces but does not return signals for image formation.

Final answer: C