All Free Biology MCQs with Answers

• A. Luteinizing hormone
• B. Follicle-stimulating hormone
• C. Testosterone
• D. lnhibin

Explanation: The hormone involved in the regulation of the rate of spermatogenesis in the male reproductive system is Follicle-stimulating hormone…

• A. Vagina
• B. Oviduct
• C. Uterus
• D. Ovary

Explanation: The cervix is the lower, narrow part of the uterus (womb). The cervix connects the main body of the uterus to the vagina (birth canal).

• A. Testosterone production
• B. FSH production
• C. Sperm production
• D. Testosterone inhibition

Explanation: Leydig cells, located in the testes, are responsible for the production and secretion of testosterone, the primary male sex hormone.

• A. Estrogen
• B. Oxytocin
• C. Progesterone
• D. LH

Explanation: Oxytocin is often referred to as the "love hormone" or "cuddle hormone." In the context of childbirth, it plays a crucial role in…

• A. Estrogen
• B. Progesterone
• C. Testosterone
• D. Thyroxin

Explanation: Testosterone is the primary male sex hormone responsible for the development of male secondary sexual characteristics, such as facial…

• A. Unisexual
• B. Bisexual
• C. Asexual
• D. Hermaphrodite

Explanation: Explanation for this question will be added soon.

• A. Globin
• B. Myoglobin
• C. Myoglycogen
• D. Glycogen

Explanation: Myoglobin is found in skeletal muscles consisting of one polypeptide chain with each molecule containing one iron-containing haem group.

• A. Smooth muscle cells
• B. Goblet cells
• C. Alveoli
• D. Epithelial cells
• E. Pleural cells

Explanation: Explanation for this question will be added soon.

• A. Internal intercostal muscles contract
• B. External intercostal muscles relax
• C. Diaphragm relaxes
• D. Occurs due to increased pressure in thoracic cavity
• E. External intercostal muscles contract

Explanation: Explanation for this question will be added soon.

• A. Larynx
• B. Trachea
• C. Bronchioles
• D. Bronchi

Explanation: Terminal Bronchioles is the last part of the conducting portion of the respiratory system, and has the smallest diameter of all (less than…

• A. 6 to 10 times per minute
• B. 10 to 14 times per minute
• C. 12 to 16 times per minute
• D. 15 to 20 times per minute

Explanation: Normal breathing rates for an adult person at rest range from 12 to 16 breaths per minute.

• A. Chemical process
• B. Biochemical process
• C. Mechanical process
• D. Both Option B and C are correct

Explanation: Respiration is both mechanical and biochemical process

• A. Carboxyhemoglobin
• B. Plasma proteins
• C. Bicarbonate ions
• D. In dissolved form

Explanation: 70% of carbon dioxide is transported in the blood as bicarbonate ions, 23% as carboxyhemoglobin and 7% in water of plasma.

• A. Glottis
• B. Voice box
• C. Epiglottis
• D. Vocal cords

Explanation: The voice box or larynx is located at the upper end of the trachea. It is a hollow chamber with cartilaginous walls and contains a pair of…

• A. Emphysema
• B. Asthma
• C. Pneumonia
• D. Bronchitis

Explanation: Pneumonia is a disease of the upper respiratory tract in which Chills, sputum production and fever is observed.

• A. Bronchi
• B. Bronchioles
• C. Windpipe
• D. Larynx

Explanation: Air from pharynx passes to larynx, which is called voice box.

• A. Glottis
• B. Epiglottis
• C. Larynx
• D. Vocal cords

Explanation: Epiglottis guards the opening of the larynx and it is flap-like in shape.

• A. 3.5 litres
• B. 2.5 litres
• C. 5.5 litres
• D. 8 litres

Explanation: The total lung capacity means the maximum amount of gas that a lung can hold. It is approximately 5-6 liters.

• A. Lungs pull air inside
• B. Passive transport of air takes place
• C. Passive expansion of air takes place
• D. Air is pushed inside

Explanation: Lungs pull air inside: This option is correct. During inspiration, the expansion of the thoracic cavity occurs passively due to the…

• A. 8
• B. 14
• C. 33
• D. 22

Explanation: The cranium has 8 bones. 14 bones are found in the fingers of each hand and also in the toes of each foot.