All Free Everyday Science MCQs with Answers

911. Deficiency of Vitamin __________ causes Sailors Disease in human?

• A. Vitamin A
• B. Vitamin K
• C. Vitamin C
• D. Vitamin D

Explanation: Vitamin C deficiency causes scurvy, historically called sailors’ disease because sailors on long voyages often lacked fresh fruits and vegetables. Vitamin D deficiency causes rickets, not scurvy.

912. People living in high altitudes (like mountains) usually have a _________?

• A. smaller number of Red Blood Cells
• B. larger number of Red Blood Cells
• C. smaller number of White Blood Cells
• D. larger number of White Blood Cells

Explanation: At high altitude, lower oxygen pressure stimulates the kidneys to release erythropoietin, increasing red blood cell production. The extra red cells help carry more oxygen to tissues.

913. The approximate intensity level of the sound which can cause damage to the ear drum is?

• A. 20 dB
• B. 60 dB
• C. 100 dB
• D. 160 dB

Explanation: Sound around 100 dB can cause pain and possible hearing damage, especially with prolonged exposure, although the exact risk depends on duration and individual susceptibility. Normal conversation is far quieter, around 60 dB.

914. What is the smallest unit of heredity?

• A. Chromosomes
• B. Gene
• C. Nucleotides
• D. none

Explanation: A gene is the basic unit of heredity, consisting of DNA that carries information for a trait or functional product. Chromosomes are larger structures containing many genes.

915. The shape of the external ear is due to____________?

• A. Elastic cartilage
• B. Fibrocartilage
• C. Articular cartilage
• D. none

Explanation: The external ear, or pinna, is shaped and supported mainly by elastic cartilage, which bends and returns to its original form. Fibrocartilage is tougher and occurs in structures such as intervertebral discs.

916. When a patient's immune system becomes reactive to a drug, this is an example of?

• A. Super infection
• B. Drug resistance
• C. Allergy
• D. none

Explanation: An immune reaction to a drug is a drug allergy, an adverse response involving the immune system. Drug resistance means a microorganism or cancer cell no longer responds effectively to treatment.

917. Which of these is not a region of the spinal cord?

• A. Thoracic
• B. Pelvic
• C. Lumbar
• D. none

Explanation: The spinal cord is divided into cervical, thoracic, lumbar, sacral, and coccygeal regions; pelvic is not one of them. The pelvis is a body region, not a spinal-cord division.

918. The autonomic nervous system innervates all of these except?

• A. Cardiac muscles
• B. Skeletal muscles
• C. Smooth muscles
• D. none

Explanation: The autonomic nervous system controls involuntary cardiac and smooth muscles, along with glands and internal organs. Skeletal muscles are controlled mainly by the somatic nervous system.

919. The damage to the_________nerve could result in the defect of the eye movement:

• A. Optic
• B. Trigeminal
• C. Abducens
• D. none

Explanation: The abducens nerve controls the lateral rectus muscle, which moves the eye outward. Damage to it causes difficulty moving the affected eye laterally, unlike the optic nerve, which mainly carries visual signals.

920. Serum if blood plasma minus its?

• A. Calcium ions
• B. Clotting proteins
• C. Globulins
• D. none

Explanation: Serum is the liquid left after blood has clotted, so it is plasma without most clotting proteins, especially fibrinogen. Globulins and calcium ions remain present in serum.