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Life Processes — Homi Bhabha Exam Biology MCQs with Solutions
Free Homi Bhabha Exam Biology Life Processes MCQs with step-by-step solutions covering Nutrition, Respiration, Transportation, Excretion. Practise online on Prepizo — no login needed.
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Sample questions with solutions
Q1 — Nutrition · hard · theory
The tiny pores on the surface of leaves through which gases are exchanged are called:
A. stomata ✓ Correct
B. veins
C. lenticels
D. root hairs
Solution: Stomata allow the exchange of CO₂ and O₂ and also the loss of water vapour.
Q2 — Nutrition · hard · theory
Amoeba takes in its food by surrounding it with finger-like extensions called:
A. tentacles
B. pseudopodia ✓ Correct
C. flagella
D. cilia
Solution: Amoeba engulfs food using pseudopodia in a process called phagocytosis.
Q3 — Nutrition · hard · theory
A plant like Cuscuta (Amarbel), which takes food from another living plant, shows:
A. parasitic nutrition ✓ Correct
B. saprophytic nutrition
C. holozoic nutrition
D. autotrophic nutrition
Solution: Cuscuta is a parasite that draws nutrients from a host plant.
Q4 — Nutrition · hard · theory
In humans, the chemical substances that speed up the digestion of food are called:
A. minerals
B. vitamins
C. hormones
D. enzymes ✓ Correct
Solution: Digestive enzymes break down complex food molecules into simpler absorbable forms.
Q5 — Respiration · hard · theory
Anaerobic respiration in yeast produces carbon dioxide and:
A. water only
B. lactic acid
C. oxygen
D. ethanol (alcohol) ✓ Correct
Solution: Yeast carries out fermentation, producing ethanol and CO₂.
Q6 — Respiration · hard · theory
During vigorous exercise, the anaerobic respiration in our muscles produces:
A. carbon dioxide only
B. glucose
C. lactic acid ✓ Correct
D. ethanol
Solution: When oxygen is scarce, muscle cells form lactic acid, which causes cramps.
Q7 — Respiration · hard · theory
Which statement correctly distinguishes breathing from respiration?
A. Breathing is a physical process; respiration is a chemical process that releases energy ✓ Correct
B. They are exactly the same
C. Breathing releases energy from food
D. Respiration is only physical
Solution: Breathing is the physical exchange of gases, while respiration is the chemical breakdown of food to release energy.
Q8 — Respiration · hard · theory
Which of the following is TRUE about plants?
A. Plants only photosynthesise
B. Plants respire all the time, taking in oxygen and giving out carbon dioxide ✓ Correct
C. Plants respire only in sunlight
D. Plants never respire
Solution: Plants respire continuously (day and night), while photosynthesis occurs only in light.
Q9 — Transportation · hard · theory
Blood vessels that carry blood away from the heart are called:
A. arteries ✓ Correct
B. veins
C. nerves
D. capillaries only
Solution: Arteries carry blood away from the heart; veins bring it back.
Q10 — Transportation · hard · theory
The loss of water vapour from the leaves of a plant, which helps pull water upward, is called:
A. transpiration ✓ Correct
B. translocation
C. photosynthesis
D. respiration
Solution: Transpiration creates a suction (pull) that draws water up through the xylem.
Q11 — Transportation · hard · theory
Human beings have double circulation, which means the blood passes through the heart:
A. never
B. twice in one complete cycle ✓ Correct
C. once in one complete cycle
D. only through the lungs
Solution: Blood flows through the heart twice per cycle (pulmonary and systemic circulation).
Q12 — Transportation · hard · theory
The colourless fluid that flows in lymph vessels and helps in defence and transport is:
A. bile
B. plasma only
C. urine
D. lymph ✓ Correct
Solution: Lymph transports digested fats and helps fight infection.
Q13 — Excretion · hard · theory
The functional (structural) unit of the kidney is the:
A. neuron
B. nephron ✓ Correct
C. alveolus
D. nephridium
Solution: Each kidney contains about a million nephrons that filter the blood and form urine.
Q14 — Excretion · hard · theory
Which organ, besides the kidneys, helps in excretion by removing carbon dioxide?
A. pancreas
B. lungs ✓ Correct
C. heart
D. stomach
Solution: The lungs excrete carbon dioxide (and some water vapour) during breathing.
Q15 — Excretion · hard · theory
Plants get rid of some waste products by:
A. urinating
B. shedding leaves and storing wastes in cells ✓ Correct
C. sweating like animals
D. using kidneys
Solution: Plants excrete wastes by shedding leaves/bark, releasing gases through stomata, and storing wastes in cells or resins.
Q16 — Nutrition · medium · theory
Organisms that make their own food from simple substances are called:
A. parasites
B. heterotrophs
C. decomposers
D. autotrophs ✓ Correct
Solution: Autotrophs (e.g. green plants) synthesise their own food by photosynthesis.
Q17 — Nutrition · medium · theory
The raw materials required for photosynthesis are carbon dioxide and:
A. nitrogen
B. oxygen
C. water ✓ Correct
D. glucose
Solution: Plants use CO₂ and water, in the presence of sunlight and chlorophyll, to make glucose and oxygen.
Q18 — Nutrition · medium · theory
The green pigment that traps sunlight for photosynthesis is:
A. melanin
B. chlorophyll ✓ Correct
C. haemoglobin
D. carotene
Solution: Chlorophyll in the chloroplasts absorbs light energy for photosynthesis.
Q19 — Nutrition · medium · theory
Fungi that obtain food from dead and decaying matter show:
A. saprophytic nutrition ✓ Correct
B. photosynthesis
C. parasitic nutrition
D. autotrophic nutrition
Solution: Saprophytes like many fungi feed on dead organic matter.
Q20 — Respiration · medium · theory
The type of respiration that takes place in the presence of oxygen is called:
A. transpiration
B. fermentation
C. anaerobic respiration
D. aerobic respiration ✓ Correct
Solution: Aerobic respiration uses oxygen and releases more energy than anaerobic respiration.
Q21 — Respiration · medium · theory
The organelle where most of the energy is released during respiration is the:
A. ribosome
B. nucleus
C. mitochondrion ✓ Correct
D. chloroplast
Solution: Mitochondria are the sites of aerobic respiration, releasing energy as ATP.
Q22 — Respiration · medium · theory
Respiration releases energy by the breakdown of:
A. water
B. oxygen
C. glucose ✓ Correct
D. carbon dioxide
Solution: Glucose is oxidised during respiration to release energy stored in it.
Q23 — Transportation · medium · theory
The organ that pumps blood throughout the human body is the:
A. kidney
B. heart ✓ Correct
C. lung
D. liver
Solution: The heart is a muscular pump that circulates blood around the body.
Q24 — Transportation · medium · theory
The red pigment in blood that carries oxygen is:
A. melanin
B. haemoglobin ✓ Correct
C. insulin
D. chlorophyll
Solution: Haemoglobin in red blood cells binds and transports oxygen.
Q25 — Transportation · medium · theory
In plants, the tissue that transports food (prepared in the leaves) to other parts is:
A. xylem
B. cambium
C. phloem ✓ Correct
D. epidermis
Solution: Phloem transports food; xylem transports water and minerals.
Q26 — Transportation · medium · theory
Which component of blood is mainly responsible for clotting?
A. plasma only
B. platelets ✓ Correct
C. white blood cells
D. red blood cells
Solution: Platelets help the blood to clot and seal wounds.
Q27 — Excretion · medium · theory
The process of removing harmful metabolic wastes from the body is called:
A. digestion
B. circulation
C. respiration
D. excretion ✓ Correct
Solution: Excretion removes toxic waste products of metabolism from the body.
Q28 — Excretion · medium · theory
The main excretory organs in human beings are the:
A. lungs
B. kidneys ✓ Correct
C. intestines
D. liver
Solution: The kidneys filter the blood and remove waste as urine.
Q29 — Excretion · medium · theory
The main nitrogenous waste excreted in human urine is:
A. glucose
B. starch
C. urea ✓ Correct
D. proteins
Solution: Urea, formed in the liver from excess amino acids, is the chief nitrogenous waste in urine.
Q30 — Excretion · medium · theory
The tube that carries urine from the kidney to the urinary bladder is the:
A. urethra
B. nephron
C. artery
D. ureter ✓ Correct
Solution: The ureter carries urine from each kidney to the bladder; the urethra removes it from the body.