All Free Everyday Science MCQs with Answers

1431. The outermost layer of skin is the__________?

• A. endodermis
• B. dermis
• C. epidermis
• D. hypodermis

Explanation: The epidermis is the skin's outer protective layer, while the dermis lies beneath it and contains vessels, nerves, and glands. The hypodermis is deeper still and is mainly fatty connective tissue.

1432. Types of bones in human body are: Long, short, irregular and ____________?

• A. Flat
• B. Medium
• C. Regular
• D. Rough

Explanation: The standard shape-based classification of bones is long, short, flat, and irregular. Flat bones include the skull bones and sternum, while the other choices are not standard bone categories.

1433. In human body there are_________________kinds of bones?

• A. 3
• B. 4
• C. 5
• D. 6

Explanation: By shape, bones are commonly grouped into four classes: long, short, flat, and irregular. Some detailed classifications add sesamoid or sutural bones, but the basic textbook list has four.

1434. Fatal degenerative lung disease caused by particulate asbestos is referred to as _____________?

• A. asbestosis
• B. asthma
• C. allergy
• D. sinusitis

Explanation: Asbestosis is a progressive lung disease caused by inhaling asbestos fibres, which scar lung tissue and reduce breathing capacity. Asthma and sinusitis have different causes and affected airways.

1435. What is the addictive drug in tobacco ______________?

• A. Ethanol
• B. Nicotine
• C. Ammonia
• D. Tar

Explanation: Nicotine is the tobacco alkaloid that produces dependence by stimulating the brain's reward pathways. Tar is a harmful mixture of smoke residues, while ammonia and ethanol are not the addictive drug asked for.

1436. How does smoking cigarettes impact the red blood cells?

• A. Decreases their ability to congeal
• B. Decreases their ability to carry oxygen
• C. Decreases their ability to reach their typical life duration
• D. Decreases their ability to cleanse wounds

Explanation: Carbon monoxide in cigarette smoke binds strongly to haemoglobin, displacing oxygen and reducing the blood's oxygen-carrying capacity. This is why smoking can deprive tissues of oxygen even when red-cell numbers are not immediately reduced.

1437. Which of the following conditions related to smoking involves damage to the alveoli sacs?

• A. Lung Cancer
• B. Atherosclerosis
• C. Emphysema
• D. Asthma

Explanation: Emphysema destroys and weakens the walls of the alveoli, reducing the surface available for oxygen and carbon dioxide exchange. Lung cancer, atherosclerosis and asthma affect the lungs or blood vessels differently.

1438. Periodontics deals with _____________?

• A. Surgery of spine
• B. Stomach disorders
• C. Ligaments restoration
• D. Dentistry
• E. Heart attacks

Explanation: Periodontics is the branch of dentistry concerned with the gums and other tissues supporting the teeth. It is not related to spinal surgery, stomach disorders or heart attacks.

1439. Circadian Rhythm refers to _____________?

• A. Planetary movements
• B. Formation of galaxies
• C. Human body cycles
• D. Calisthenics

Explanation: A circadian rhythm is an approximately 24-hour biological cycle, such as the sleep-wake cycle and daily changes in body temperature. It describes biological timing, not planetary or galactic movement.

1440. Which of the following is a mammal?

• A. Ostrich
• B. Crocodile
• C. Platypus
• D. Duck

Explanation: The platypus is a mammal even though it lays eggs, because it has hair and produces milk for its young. Ostriches and ducks are birds, while crocodiles are reptiles.