All Free Biology MCQs with Answers

2021. Outer surface of bones is covered by a dense layer of connective tissue, called as ___________ ?

• A. Periosteum
• B. Woven bone
• C. Epithelium lining
• D. Connective lining

Explanation: The periosteum is a dense connective-tissue covering around the outer surface of most bones; it contains blood vessels, nerves and bone-forming cells. Students may choose epithelium lining, but bone is covered by connective tissue rather than epithelial tissue.

2022. Which of the following vitamins is useful in ostcoimalacia?

• A. Vitamin D
• B. Vitamin E
• C. Vitamin C
• D. Vitamin A

Explanation: Vitamin D promotes intestinal absorption of calcium and phosphate, enabling proper mineralization of bone; its deficiency causes osteomalacia in adults. Students may choose vitamin C because it is also important for connective tissue and bone health, but it does not correct the defective mineralization characteristic of osteomalacia.

2023. Which is not a vertebrate ?

• A. Reptiles
• B. Fish
• C. Insect
• D. None of these

Explanation: Vertebrates possess a vertebral column or backbone, whereas insects are invertebrate arthropods and lack a backbone. A student may choose reptiles because some reptiles crawl, but locomotion and body covering do not determine whether an animal is a vertebrate.

2024. Which bone is called beauty bone in women?

• A. sternum
• B. clavicle
• C. maxilla
• D. radius

Explanation: The clavicle, or collarbone, is called the beauty bone because it forms the visible line between the neck and shoulder and helps support the shoulder. The sternum may be chosen because it is another chest bone, but it is not the prominent collarbone meant by this term.

2025. Which of the following bones are present in pectoral girdle?

• A. Clavicle
• B. Scapula
• C. Both of these
• D. None of these

Explanation: The pectoral girdle consists of a clavicle and a scapula on each side, linking the upper limb to the axial skeleton. Students may choose either a or b by remembering only one bone, but both bones form the girdle.

2026. How many vertebrae are present in lumbar region?

• A. 7
• B. 12
• C. 5
• D. 4

Explanation: The lumbar region contains five vertebrae, numbered L1 to L5, and supports much of the body's weight. Students may choose b because the thoracic region has 12 vertebrae, but 12 is not the count for the lumbar region.

2027. How many vertebrae are in sacrum?

• A. 7
• B. 12
• C. 5
• D. 4Standardized & Admissions Tests

Explanation: The sacrum is formed by the fusion of five sacral vertebrae, creating a strong bone between the two hip bones. Students may choose d because the coccyx commonly contains four fused vertebrae, but those vertebrae form the coccyx rather than the sacrum.

2028. How many vertebrae are present in thoracic region?

• A. 7
• B. 12
• C. 5
• D. 4Aquaculture

Explanation: The thoracic region contains 12 vertebrae, and each one articulates with ribs to help form the thoracic cage. The likely distractor is 7 vertebrae, which is the number of cervical vertebrae in the neck.

2029. Which of the following pairs of fins in a fish body are paired?

• A. Dorsal and ventral.
• B. Pectoral and Pelvic.
• C. Tail and anal
• D. All of these

Explanation: Pectoral fins and pelvic fins are paired because they occur as corresponding structures on the left and right sides of the fish. The dorsal, ventral, tail and anal fins are generally median fins, so a student may incorrectly choose all of these.

2030. Which of the following vertebrates have a fish-like body?

• A. Reptiles
• B. Aves
• C. Amphibians
• D. Mammals.

Explanation: Amphibians, especially their aquatic larvae, show a fish-like body form and are adapted for swimming in water. The likely distractor is reptiles, but reptiles generally have a more terrestrial body plan with well-developed limbs or scales.