30. The presence of which of the following does NOT let the air passage in the respiratory system of humans collapse when there is less air in it?
[RRB Group D, 6 September 2022, Shift 1]
(a) Tendons
(b) Ligaments
(c) Rings of cartilage
(d) Muscles
Answer: (c) Rings of cartilage
Explanation: C-shaped rings of hyaline cartilage reinforce the trachea and help keep its lumen open despite pressure changes during breathing. Their incomplete posterior portion also allows expansion of the oesophagus during swallowing. Ligaments and tendons perform different supportive roles.
29. Which of the following tissues helps in tissue repair?
[RRB Group D, 16 September 2022, Shift 3]
(a) Tendon
(b) Ligament
(c) Areolar
(d) Cartilage
Answer: (c) Areolar
Explanation: Areolar tissue is loose connective tissue found between organs, around vessels and beneath epithelia. Fibroblasts in this tissue produce repair-associated extracellular matrix, and immune cells participate in healing. Dense tendon and ligament tissue generally heal more slowly.
28. Where in a human body can anaerobic respiration take place?
[RRB Group D, 30 September 2022, Shift 2]
(a) Only in striated muscle cells
(b) In the cytoplasm of cells
(c) In mitochondria of all cells
(d) Only in red blood cells in the veins
Answer: (b) In the cytoplasm of cells
Explanation: Glycolysis occurs in the cytoplasm, where ATP can be produced without oxygen. During intense muscle activity, pyruvate may be converted to lactate, regenerating NAD+ needed for glycolysis. Anaerobic ATP generation is not restricted exclusively to skeletal muscle.
27. How many bones form the axial skeleton?
[NVS Staff Nurse, 8 March 2022]
(a) 126 bones
(b) 80 bones
(c) 206 bones
(d) 70 bones
Answer: (b) 80 bones
Explanation: The adult axial skeleton contains 80 bones, including cranial and facial bones, auditory ossicles, hyoid, vertebral column, ribs and sternum. The appendicular skeleton contributes 126 bones of the limbs and girdles, together giving the standard total of 206.
26. Which of the following connects a bone to bone?
[WBCS Mains 2021 cycle, Paper IV, held May 2022]
(a) Cartilage
(b) Ligament
(c) Tendon
(d) Interstitial fluid
Answer: (b) Ligament
Explanation: A ligament connects adjacent bones and stabilizes their articulation. Tendons connect muscles to bones; cartilage makes joint surfaces resilient and smooth. Joint stability depends on a combination of ligament tension, bony shape and surrounding muscle control.
25. Which is the largest joint in the human body?
[RRB NTPC CBT I, 5 April 2021, Shift 2]
(a) Knee joint
(b) Neck joint
(c) Pelvic joint
(d) Shoulder joint
Answer: (a) Knee joint
Explanation: The knee is the largest joint in the human body and bears substantial weight during walking, running and jumping. It joins the femur and tibia, with the patella positioned anteriorly, and incorporates menisci, ligaments and synovial fluid.
24. There are 29 bones in the human head. Which of the following classifications is correct?
[RRB NTPC CBT I, 3 April 2021, Shift 1]
(a) Cranial-8, Facial-14, Ear-6, Hyoid-1
(b) Cranial-8, Facial-12, Ear-6, Hyoid-3
(c) Cranial-8, Facial-14, Ear-4, Hyoid-3
(d) Cranial-8, Facial-12, Ear-8, Hyoid-1
Answer: (a) Cranial-8, Facial-14, Ear-6, Hyoid-1
Explanation: Counting the skull with associated ear ossicles and hyoid gives 29 bones: eight cranial, fourteen facial, six middle-ear ossicles and one hyoid. The anatomical skull itself is commonly described as twenty-two bones, excluding ossicles and hyoid.
23. Which is the smallest bone of the human body?
[RRB NTPC CBT I, 8 March 2021, Shift 1]
(a) Femur
(b) Stapes
(c) Humerus
(d) Malleus
Answer: (b) Stapes
Explanation: The stapes is the smallest of the auditory ossicles in the middle ear. Its footplate transfers mechanical vibrations to the oval window of the inner ear. The femur is the longest bone, while the humerus belongs to the upper arm.
22. The number of bones in an adult human body is:
[RRB NTPC CBT I, 9 January 2021, Shift 2]
(a) 206
(b) 156
(c) 16
(d) 296
Answer: (a) 206
Explanation: The conventional adult skeleton consists of 206 bones, partitioned into 80 axial and 126 appendicular elements. Babies have more separately developing skeletal parts because some bones later fuse. Individual adult counts can vary because of accessory bones.
21. The smallest and longest bones in the human body are ________ and _________, respectively.
[SSC GD Constable, 26 November 2021, Shift 3]
(a) Stapes, fibula
(b) Tibia, femur
(c) Stapes, femur
(d) Nails, fibula
Answer: (c) Stapes, femur
Explanation: The stapes is a minute bone in the middle ear involved in hearing. The femur, extending from hip to knee, is the longest and among the strongest bones. The fibula is a smaller long bone of the lower leg.
