All Free Biology MCQs with Answers

2011. Lungs are spongy due to the presence of million of___________?

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

Explanation: The lungs are spongy because they contain millions of alveoli, tiny air sacs surrounded by capillaries that provide a large surface area for gas exchange. Students may choose bronchioles because they branch extensively inside the lungs, but bronchioles are air passages and do not provide the main exchange surface.

2012. An infectious disorder of respiratory system is_________________?

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

Explanation: Tuberculosis is an infectious respiratory disease caused mainly by Mycobacterium tuberculosis and can spread through airborne droplets. Asthma, emphysema and most lung cancers are not infectious disorders, although students may choose asthma because it is also a common breathing problem.

2013. What is the heaviest organ in human body?

• A. Liver
• B. Skin
• C. Intestine
• D. Brain

Explanation: The skin is generally regarded as the heaviest organ of the human body, with its mass including the epidermis, dermis and associated tissues. The liver is the heaviest internal organ, but it weighs less than the entire skin. Students may choose liver because it is the largest internal gland and organ, confusing internal-organ size with total organ mass.

2014. What is the number of 'True Ribs' in human body?

• A. 12
• B. 14
• C. 16
• D. 18

Explanation: Humans have 12 pairs of ribs, and the first seven pairs attach directly to the sternum; these are called true ribs. Therefore, 7 pairs x 2 ribs per pair = 14 true ribs. Students may choose 12 by counting pairs as individual ribs or may choose 18 by confusing true ribs with the total number of ribs.

2015. The study of bone is called as ___________?

• A. Chondrology
• B. Osteology
• C. Mycology
• D. Histology

Explanation: Osteology is the branch of anatomy concerned with bones and the skeletal system. Students may choose chondrology because cartilage is another skeletal connective tissue, but chondrology specifically concerns cartilage, not bone.

2016. Tibia bone is in the body _____________?

• A. Leg
• B. Ear
• C. Hand
• D. Nose

Explanation: The tibia is the larger medial bone of the lower leg, extending from the knee to the ankle and bearing much of the body's weight. A student may choose the hand because both the tibia and hand contain long bones, but the tibia is specifically a leg bone.

2017. How many bones does a baby have_______?

• A. 212
• B. 206
• C. 300
• D. None of these

Explanation: A human baby has about 300 bones because many skeletal elements are still separate. During growth, several bones fuse, reducing the adult total to 206, which is why students may incorrectly choose option b.

2018. The pelvic girdle connect the leg with_________?

• A. Vertebral column
• B. Rib cage
• C. Skull
• D. Shoulder

Explanation: The pelvic girdle attaches the lower limbs to the axial skeleton through the hip bones, which connect with the sacrum of the vertebral column. The shoulder is also a girdle connecting a limb to the trunk, so it may be chosen by students who confuse the pelvic and pectoral girdles.

2019. Smallest bone of human body is?

• A. vomer
• B. stapes
• C. navicular
• D. occipital

Explanation: The stapes is the smallest bone in the human body and lies in the middle ear, where it transmits vibrations toward the inner ear. The vomer is also a small bone, but it forms part of the nasal septum and is larger than the stapes.

2020. The skull contains?

• A. 18 bones
• B. 20 bones
• C. 22 bones
• D. 28 bones

Explanation: The skull has 22 bones in the usual anatomical count: 8 cranial bones plus 14 facial bones, giving 8 + 14 = 22 bones. Students may choose 28 if they include some small ear bones or other nearby bones that are not part of the skull count.