All Free Biology MCQs with Answers

• A. Kidney
• B. Heart
• C. Brain
• D. Lungs

Explanation: Option A: The kidney is covered by a tough renal capsule. Options B : The heart is enclosed in a double membranous sac - the pericardial…

• A. 1
• B. 2
• C. 3
• D. 4

Explanation: Option A is wrong because it is a fact. Each nasal cavity is not subdivided into 1 passageway.

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

Explanation: "Tiny air sacs at the end of the bronchioles (tiny branches of air tubes in the lungs).

• A. 10 to 15 times per minute
• B. 10 to 20 times per minute
• C. 80 to 120 times per minute
• D. 30-40 times per minute

Explanation: When you exercise and your muscles work harder, your body uses more oxygen and produces more carbon dioxide.

• A. Alveoli
• B. Diaphragm
• C. Epithelial membrane
• D. Pleura

Explanation: D is correct becauseThe lungs are surrounded by a thin double-layered membrane known as the Pleural membrane.

• A. 2
• B. 3
• C. 4
• D. 5

Explanation: Option A is the correct option because There are two different types of bronchitis, acute and chronic.

• A. 15-20 times per minute
• B. 30 times per minute
• C. 20 times per minute
• D. 10-20 times per minute

Explanation: When you exercise and your muscles work harder, your body uses more oxygen and produces more carbon dioxide.

• A. Emphysema
• B. Asthma
• C. Pneumonia
• D. Bronchitis

Explanation: All off these symptoms are usually of bronchitis Symptoms of emphysema are frequent coughing or wheezing or cough that produces a lot of…

• A. Bronchi
• B. Bronchioles
• C. Pharynx
• D. Alveolar duct

Explanation: the main airways (bronchi) branch off into smaller and smaller passageways - the smallest, called bronchioles.

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

Explanation: The part of the respiratory system that has the thinnest wallwal and also the smallest diameter is bronchiole.

• A. Collapsing
• B. Vibrating
• C. Swelling
• D. Breaking

Explanation: C-shaped cartilaginous rings reinforces the anterior and lateral sides of the trachea to protect and maintain the airway open.

• A. Voice box
• B. Bronchioles
• C. Vocal cords
• D. Vocal duct

Explanation: The vocal folds, also known as vocal cords, are located within the larynx at the top of the trachea.

• A. No effect on surface tension
• B. Increasing surface tension
• C. Decreasing surface tension
• D. None of these

Explanation: Pulmonary surfactant is essential for life as it lines the alveoli to lower surface tension, thereby preventing atelectasis during…

• A. Alveoli
• B. Trachea
• C. Diaphragm
• D. Bronchi

Explanation: Alveoli are tiny ball-shaped air sacs which inflate and deflate, and thus, make the lungs spongy.

• A. Shoot apex of mature stem
• B. Embryo of the seed
• C. Leaves of the plants
• D. All of these

Explanation: Whenever vernalization occurs in the mature plants, the receptor of stimulus is the stem apex and embryo tips.

• A. 3
• B. 2
• C. 5
• D. 6

Explanation: The two types of bronchitis are acute and chronic bronchitis.

• A. Intercostal muscles are contracted
• B. Ribs are relaxed
• C. Muscles of the diaphragm are relaxed
• D. Lungs are relaxed

Explanation: When the lungs exhale, the diaphragm relaxes, and the volume of the thoracic cavity decreases, while the pressure within it increases.

• A. HCl
• B. Mucus
• C. Enzymes
• D. Amylase

Explanation: Goblet cells are unicellular glands that are present in the lining of the respiratory and digestive tracts.

• A. Hemoglobin
• B. Myoglobin
• C. Myosin
• D. Actinomyosin

Explanation: Myoglobin is a protein present in muscles, which has one oxygen-binding site, and its function is to supply muscles constantly with oxygen.

• A. 6.7 litres
• B. 2.5 litres
• C. 7 litres
• D. 5 litres

Explanation: In an adult human being when the lungs are fully inflated the total inside capacity of lungs is about 5 litres. (PTB)