The digestive and respiratory system share some common spaces. The digestive system is composed of the mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum and anus.

The correct answer is option 'C', which is the oropharynx. The oropharynx is a common passage for both the digestive and respiratory systems because it serves as a junction where food and air pass through.

Below is a detailed explanation of why the oropharynx is the common passage for both systems:

1. Definition of the oropharynx:
The oropharynx is a part of the throat located behind the mouth, extending from the soft palate to the epiglottis. It is responsible for conducting both food and air.

2. Role in the digestive system:
The oropharynx plays a crucial role in the digestive system as it serves as a passage for food. When we eat, food enters the mouth and passes through the oropharynx before reaching the esophagus, which leads to the stomach. In the oropharynx, the food is mixed with saliva and formed into a bolus, which is then pushed down into the esophagus by swallowing. From there, the digestive process continues.

3. Role in the respiratory system:
The oropharynx is also an essential part of the respiratory system. It serves as a connection between the nasal and oral cavities and the larynx. When we breathe, air enters through the nose or mouth, passes through the oropharynx, and then enters the larynx. The larynx, commonly known as the voice box, is located below the oropharynx and is responsible for producing sound and allowing air to enter the trachea.

4. Common functions and characteristics:
The oropharynx has certain characteristics that make it suitable as a common passage for both systems. It is lined with a protective layer of mucus, which helps lubricate and protect the tissues from damage. Additionally, the oropharynx contains tonsils, which play a role in immune defense by filtering out harmful bacteria and viruses.

In conclusion, the oropharynx acts as a common passage for both the digestive and respiratory systems. It allows food to pass from the mouth to the esophagus for digestion and also serves as a pathway for air to enter the larynx and trachea for respiration. Its location and characteristics make it an important and efficient junction for these two vital systems.

Yaaa pharynx is the common passage for both digestive and respiratory systems.......epiglottis is the flap like structure that controls the passage of food and air at pharunx