All Free Biology MCQs with Answers

• A. 44 times/minute
• B. 40 times/minute
• C. 25 times/minute
• D. 20 times/minute

Explanation: The breathing rate decreases with age. Some average breathing rates are given below: 2-5 years= 25-30 breaths/min 5-12 years= 20 to 25…

• A. Trachea
• B. Bronchus
• C. Bronchioles
• D. Tracheoles

Explanation: The correct answer is Bronchioles. Bronchioles do not contain cartilage, unlike the trachea and bronchi, which have cartilage to maintain…

• A. 19.4 ml
• B. 19.6 ml
• C. 20 ml
• D. 21 ml

Explanation: In 100 ml of blood, there is about 15 g of hemoglobin, which can bind approximately 20.1 ml of oxygen.

• A. 77%
• B. 90%
• C. 87%
• D. 97%

Explanation: Red blood cells (also known as erythrocytes) contain a protein called hemoglobin, which carries oxygen from the lungs to all parts of the…

• A. 5%
• B. 6%
• C. 7%
• D. 8%

Explanation: Carbon dioxide (CO2) is transported in the blood in three main forms. Approximately 7% of CO2 is transported bound to plasma proteins…

• A. Embolism
• B. Atherosclensis
• C. Cyanosis
• D. Arteriosclerosis

Explanation: Cyanosis indicates there may be decreased oxygen attached to red blood cells in the bloodstream.

• A. Flagellated endothelium
• B. Flagellated epithelium
• C. Ciliated epithelium
• D. All of the above

Explanation: The nasal cavity is lined with a mucous membrane that contains a specialized type of epithelium called ciliated epithelium.

• A. Support
• B. Keep passage open
• C. Prevent collapsing
• D. All of the above

Explanation: A. Support: The rings provide structural support to the trachea and bronchi, helping to maintain their shape and prevent collapse during…

• A. Ribs and trachea
• B. Intercostal muscles
• C. Ribs & intercostal muscles
• D. Ribs, intercostal muscles & diaphragm

Explanation: Option C, "Ribs & intercostal muscles," is the correct answer. The lateral walls of the chest cavity in humans are primarily composed of…

• A. Dorsal
• B. Ventral
• C. Medial
• D. Lateral

Explanation: The trachea (windpipe) is located ventral (in front of) the esophagus in the thoracic cavity.

• A. 37
• B. 35
• C. 34
• D. 33

Explanation: Vertebrae are the 33 individual bones that interlock with each other to form the spinal column.

• A. 2
• B. 3
• C. 4
• D. 5

Explanation: Refer to the diagram below.The number of vertebrae in the coccyx is 4.

• A. Two
• B. Three
• C. Four
• D. Five

Explanation: The sacrum is a large, triangular bone located at the base of the vertebral column, between the lumbar vertebrae and the coccyx.

• A. 37
• B. 35
• C. 34
• D. 33

Explanation: This option is correct. The vertebral column in humans consists of 33 vertebrae, including 7 cervical vertebrae, 12 thoracic vertebrae, 5…

• A. Haversian canal
• B. Periosteum
• C. Marrow
• D. Joint

Explanation: The correct answer is the Haversian canal. These canals are part of the microscopic structure of compact bone and facilitate the…

• A. Red
• B. Yellow
• C. Orange
• D. Both (A) and (B)

Explanation: Bone marrow is the soft tissue inside bones. There are two types: red bone marrow, which is involved in blood cell production, and yellow…

• A. Collagenous fibers
• B. Blood vessels
• C. Perichondrium
• D. Matrix

Explanation: The correct answer is the 'Matrix.' The matrix is essential for the regeneration of cartilage as it provides a scaffold for cellular…

• A. Calcification
• B. Chondrification
• C. Decalcification
• D. Ossification

Explanation: Ossification is the correct term for the process of bone formation, also known as osteogenesis.

• A. Perichondrium
• B. Prostomium
• C. Perimycium
• D. Periosteum

Explanation: The correct answer is periosteum. The periosteum is a dense fibrous membrane covering the surface of bones.

• A. Osteoclast
• B. Osteoblasts
• C. Osteocytes
• D. Fibroblast

Explanation: Osteoclasts are the bone-dissolving cells responsible for bone resorption.