Answer:
The correct answer is A: trachea. The air goes from the pharynx (throat) to the trachea (windpipe) in the respiratory system. Here is a detailed explanation of the pathway of air:
Pharynx:
- The pharynx is the region at the back of the throat where both food and air pass through.
- It serves as a common pathway for both the digestive and respiratory systems.
Trachea:
- The trachea, also known as the windpipe, is a tube-like structure that connects the pharynx to the lungs.
- It is made up of C-shaped rings of cartilage, which provide support and prevent the trachea from collapsing.
- The trachea is lined with tiny hair-like structures called cilia, which help to filter and remove any foreign particles from the air.
Bronchi:
- The trachea divides into two main branches called bronchi.
- The bronchi are further divided into smaller branches called bronchioles, forming a branching network in the lungs.
Bronchioles:
- The bronchioles are small, thin-walled tubes that carry air from the bronchi to the alveoli (small air sacs in the lungs).
- They do not have cartilage like the trachea and bronchi, but they have smooth muscles that help regulate airflow.
In summary, the air travels from the pharynx to the trachea, then to the bronchi, and finally to the bronchioles.