1. Which organ in humans is responsible for the ultrafiltration of blood?
A) Kidney
B) Liver
C) Lungs
D) Intestine
Ultrafiltration occurs in the Bowman's capsule of the nephron in the kidney.
2. Which component of blood transports oxygen?
A) Plasma
B) White blood cells
C) Red blood cells
D) Platelets
Red blood cells contain hemoglobin which carries oxygen throughout the body.
3. Which hormone regulates the basal metabolic rate?
A) Thyroxine
B) Insulin
C) Adrenaline
D) Cortisol
Thyroxine secreted by the thyroid gland controls the metabolic rate.
4. Where does fertilization occur in human females?
A) Uterus
B) Fallopian tube
C) Cervix
D) Vagina
Fertilization occurs in the ampullary-isthmic junction of the fallopian tube.
5. Which blood vessel carries deoxygenated blood from the heart to the lungs?
A) Pulmonary artery
B) Pulmonary vein
C) Aorta
D) Renal artery
The pulmonary artery carries deoxygenated blood from the right ventricle to the lungs.
6. Which of the following is a connective tissue?
A) Epithelium
B) Muscle
C) Nervous tissue
D) Blood
Blood is considered a fluid connective tissue due to its origin and function.
7. Which part of the brain regulates body temperature?
A) Cerebrum
B) Hypothalamus
C) Cerebellum
D) Medulla
The hypothalamus regulates body temperature, hunger, and thirst.
8. The functional unit of the kidney is called:
A) Alveolus
B) Neuron
C) Nephron
D) Osteon
Each nephron filters blood and forms urine in the kidney.
9. Which enzyme in saliva breaks down starch?
A) Salivary amylase
B) Lipase
C) Pepsin
D) Trypsin
Salivary amylase (ptyalin) initiates carbohydrate digestion in the mouth.
10. What is the main nitrogenous waste excreted in human urine?
A) Urea
B) Ammonia
C) Creatinine
D) Uric acid
Urea is the major nitrogenous waste product of protein metabolism in humans.
11. Which type of immunity is provided by colostrum to a newborn?
A) Passive natural immunity
B) Active natural immunity
C) Artificial active immunity
D) Autoimmunity
Colostrum contains antibodies that provide passive natural immunity to infants.
12. Which plant hormone is known as the stress hormone?
A) Auxin
B) Abscisic acid
C) Cytokinin
D) Gibberellin
Abscisic acid helps plants cope with stress by closing stomata and inhibiting growth.
13. Which of the following carries oxygenated blood?
A) Pulmonary artery
B) Right atrium
C) Pulmonary vein
D) Superior vena cava
Pulmonary vein carries oxygen-rich blood from lungs to the left atrium.
14. Which mineral element is a component of chlorophyll?
A) Magnesium
B) Iron
C) Potassium
D) Calcium
Magnesium is at the center of the chlorophyll molecule and essential for photosynthesis.
15. Which part of the brain controls voluntary movements?
A) Cerebrum
B) Cerebellum
C) Hypothalamus
D) Medulla
The cerebrum controls voluntary movements, speech, and thought processes.
16. Which of the following is a vestigial organ in humans?
A) Appendix
B) Liver
C) Kidney
D) Pancreas
The appendix is a vestigial organ — no significant role in digestion in modern humans.
17. Which process involves conversion of ammonia into urea?
A) Ammonification
B) Nitrification
C) Ureotelism
D) Denitrification
Ureotelism is the process by which ammonia is converted into less toxic urea in humans.
18. In which organelle does the Krebs cycle occur?
A) Nucleus
B) Mitochondria
C) Chloroplast
D) Ribosome
The Krebs cycle (TCA cycle) occurs in the matrix of mitochondria, producing ATP.
19. Which structure in a neuron receives impulses?
A) Dendrites
B) Axon
C) Synapse
D) Schwann cell
Dendrites receive incoming nerve impulses and transmit them to the cell body.
20. Which gas is fixed during photosynthesis?
A) Carbon dioxide
B) Oxygen
C) Nitrogen
D) Hydrogen
Carbon dioxide from the air is fixed into glucose during the Calvin cycle of photosynthesis.
