All Free Biology MCQs with Answers

• A. Asthma
• B. Tuberculosis
• C. Emphysema
• D. A and B

Explanation: Emphysema is one of the diseases that comprises COPD (chronic obstructive pulmonary disease).

• A. 2
• B. 5
• C. 8
• D. More than 10

Explanation: The correct answer is "D". Tobacco smoke is made up of thousands of chemicals, including at least 70 known to cause cancer.

• A. 19.6ml/100 ml blood
• B. 20 ml/100 ml blood
• C. 25 ml/100 ml blood
• D. 30 ml/100 ml blood

Explanation: The maximum amount of oxygen which normal human blood absorbs and carries at sea-level is about 20ml/100 ml of blood.

• A. Pharynx
• B. Bronchioles
• C. Nostrils
• D. None of these

Explanation: Nostrils are the openings to the nasal cavities that are on the face. These air-filled pockets are connected to nasal cavities of the nose.

• A. Contract
• B. Increase
• C. Decrease
• D. Damage

Explanation: Option A: Incorrect. The muscles involved in inspiration actually contract, causing the thoracic cavity to expand.

• A. Possess more RBCs with haemoglobin of low O2 binding affinity
• B. Possess same RBCs with haemoglobin of high O2 binding affinity
• C. Lose physical fitness to play games like football
• D. Suffer from altitude sickness with nausea and fatigue

Explanation: When one is at a high altitude, he/she has to acclimatize to it. Breathing becomes difficult at high altitudes, because of the low density…

• A. CO2 in air
• B. Moisture in expired air
• C. O2 in air
• D. All of these

Explanation: Option A: Carbon dioxide (CO2) is a gas that is naturally present in the Earth's atmosphere.

• A. Pharynx
• B. Bronchioles
• C. Bronchi
• D. Both B and C

Explanation: The pharynx is a muscular tube-shaped structure that connects the nasal cavity and mouth to the oesophagus and larynx.

• A. 20
• B. 30
• C. 35
• D. 45

Explanation: The age at which a person may develop chronic bronchitis can vary depending on various factors such as genetics, lifestyle, and exposure…

• A. Bronchioles
• B. Windpipe
• C. Bronchi
• D. Alveoli

Explanation: Alveoli are tiny air sacs in your lungs that take up the oxygen you breathe in and keep your body going.

• A. Lungs
• B. Trachea
• C. Glucagon
• D. Bronchi

Explanation: All of the above mentioned organs are involved in breathing one way or another except glucagon

• A. Lungs
• B. Bronchi
• C. Trachea
• D. Nostrils

Explanation: Nostrils; These are the openings to the nasal cavities that are on the face. Air enters the nasal cavity through these openings

• A. Tobacco smoking
• B. Chemicals
• C. Pollutants
• D. Mutagens

Explanation: Tobacco cigarettes contain nicotine and tar which acts as a carcinogen. Carcinogens are cancer causing chemicals.

• A. Bronchi
• B. Bronchioles
• C. Windpipe
• D. Larynx

Explanation: The incoming air passes from the pharynx to the larynx then to the windipe (trachea).

• A. Pleural membrane
• B. Myocardium
• C. Pericardium
• D. Both Options B and C are correct

Explanation: Option A; The pleura includes two thin layers of tissue that protect and cushion the lungs.

• A. Ribs
• B. Pharynx
• C. Lungs
• D. Both B and C

Explanation: The ribs are supported by intercostal muscles which form the walls of the thoracic cavity and also move the ribs during breathing.

• A. Bronchioles
• B. Bronchi
• C. Alveoli
• D. Air sac

Explanation: Bronchioles are approximately 1 mm or less in diameter and their walls consist of ciliated cuboidal epithelium and a layer of smooth…

• A. Smoking
• B. Cough
• C. Pollutants
• D. Mutagens

Explanation: Smoking is the number one cause of lung cancer. It causes about 90 percent of lung cancer cases.

• A. Breakdown of glucose
• B. Formation of ATP
• C. Release of energy
• D. Exchange of gases

Explanation: The oxidation-reduction processes occur inside the living cells during which organic food is broken down and energy is released.C6H12O6 +…

• A. Voice box
• B. Epiglottis
• C. Bronchi
• D. Wind pipe

Explanation: OPTION A: The larynx is an enlargement in the airway at the top of the trachea and below the pharynx.