The question asks for the biological process responsible for the exchange of oxygen from the atmosphere and carbon dioxide produced by cells. This is a fundamental concept in biology, specifically related to the respiratory system.
A) Breathing (respiration) — This term accurately describes the process of gas exchange where oxygen is taken in from the atmosphere and carbon dioxide, a waste product from cellular metabolism, is released. It encompasses both the mechanical act of breathing and the physiological gas exchange.
The question asks about the average breathing rate of a healthy adult human. This is a standard physiological fact that competitive exam aspirants should be aware of. We need to identify the option that correctly states this average rate.
C) 12–16 times. The normal respiratory rate for a healthy adult at rest is typically between 12 and 20 breaths per minute. The option 12–16 times falls well within this accepted physiological range.
The question asks to identify the specific anatomical structure responsible for preventing food from entering the larynx (windpipe) during the act of swallowing. This is a direct recall question from human anatomy, specifically the respiratory and digestive systems.
Correct Option: C) Epiglottis
The question asks to identify the structure in humans commonly known as the 'sound box' or 'voice box'. This requires knowledge of the anatomy and function of the human respiratory and vocal systems.
Correct Option: B) The larynx, also known as the voice box, is a cartilaginous structure located in the neck, at the top of the trachea. It contains the vocal cords, which vibrate when air passes through them, producing sound. This sound is then modulated by the pharynx, tongue, and lips to form speech.
The question asks about the anatomical landmark where the trachea bifurcates into the two main bronchi. This is a standard anatomical fact related to the respiratory system.
Correct Option: C) 5th thoracic vertebra
The question asks to identify the specific location within the human lungs where the exchange of gases (oxygen and carbon dioxide) occurs. This requires knowledge of the anatomy and function of the respiratory system.
Therefore, the alveoli are the primary sites for gaseous exchange.
Correct Option: B) Alveoli — The alveoli are tiny, balloon-like structures in the lungs where the actual exchange of oxygen and carbon dioxide between the air and the blood takes place. Their thin walls and large surface area are perfectly adapted for this function.