The correct answer is Larynx.

Key Points 

• The larynx is also known as voice box.
• It is a cartilaginous box that helps in sound production and hence it is called soundbox.
• It is a flexible tube where air passes between back of pharynx and trachea.
• It is generally made of cartilage and muscle and is lined with a mucus membrane.
• The larynx helps to provide smooth passage of air from nasal cavity to lungs.
• When we swallow food, epiglottis covers opening of larynx to keep food and drink from entering airways.
• It is located in neck.
• Functions:
  • swallowing
  • breathing
  • voice production
• The vocal cords vibrate when air passes through m.
• This creates sound waves in pharynx, nose, and mouth.

The correct answer is option 3, i.e Pleura.

• Pleura is membrane that will cover lungs, it is a double-layered membrane between double layer membrane and a jelly-like fluid is also present to lower friction on long surface.  
• Diaphragm: It is located below lungs. It is major muscle of respiration system, It is a dome-shaped muscle that contracts and expands rhythmically and involuntarily. Upon inhalation, diaphragm contracts and flattens and chest cavity enlarges.

Additional Information