Which class of animals exhibits the phenomenon of holometabolous development?
Answer: A
Insects undergo complete metamorphosis with distinct larval, pupal, and adult stages, a characteristic holometabolous development.
Q.22Easy
Which of the following organisms possesses both a radula and a muscular foot?
Answer: C
Snails (gastropod mollusks) characteristically have both a radula (feeding structure) and a ventral muscular foot for locomotion.
Q.23Easy
Which of the following represents an adaptation for flight in birds that is NOT found in other vertebrates?
Answer: C
Feathers are unique to birds and provide insulation and aerodynamic surfaces essential for flight, while other options are found in other vertebrate classes.
Q.24Easy
A newly discovered organism has the following characteristics: exoskeleton, jointed appendages, and open circulatory system. To which phylum does it belong?
Answer: A
The combination of exoskeleton, jointed appendages, and open circulatory system is diagnostic of Arthropoda.
Q.25Easy
In cnidarians, the tentacles surrounding the mouth region contain specialized cells called cnidocytes. What is their primary function?
Answer: B
Cnidocytes contain nematocysts that discharge and inject toxins, allowing cnidarians to capture and immobilize prey organisms.
Advertisement
Q.26Easy
A researcher observes an animal with chitinous exoskeleton, book lungs, and eight walking legs. Which class does this organism belong to?
Answer: B
The combination of eight legs, chitinous exoskeleton, and book lungs is diagnostic of Class Arachnida (spiders, scorpions, ticks).
Q.27Easy
Which of the following is the primary function of the glomerulus in the nephron?
Answer: A
The glomerulus is a network of capillaries where ultrafiltration occurs, filtering small molecules like glucose, ions, and urea from blood into Bowman's capsule.
Q.28Easy
The hormone that increases blood glucose concentration is:
Answer: B
Glucagon, secreted by alpha cells of pancreatic islets, increases blood glucose through glycogenolysis and gluconeogenesis.
Q.29Easy
Which enzyme initiates protein digestion in the stomach?
Answer: B
Pepsin is a protease secreted by gastric glands that begins protein digestion in the acidic environment of the stomach.
Q.30Easy
The cardiac cycle duration in a normal adult is approximately:
Answer: B
A complete cardiac cycle takes approximately 0.8 seconds at a heart rate of 72 beats per minute.
Q.31Easy
Which structure in the brain is responsible for maintaining body equilibrium and balance?
Answer: B
The cerebellum coordinates voluntary movements and maintains body balance through proprioceptive feedback.
Q.32Easy
During inspiration, the diaphragm contracts and moves:
Answer: B
Diaphragm contraction flattens it and moves downward, increasing thoracic cavity volume and decreasing intra-pulmonary pressure.
Q.33Easy
Which hormone is primarily responsible for increasing blood glucose levels during the fight-or-flight response?
Answer: A
Epinephrine (adrenaline) is released by the adrenal medulla during stress and increases blood glucose by promoting glycogenolysis and inhibiting insulin secretion.
Q.34Easy
The blood-brain barrier is primarily composed of which type of cell?
Answer: A
The blood-brain barrier is formed by tight junctions between endothelial cells of brain capillaries, supported by astrocytes that regulate nutrient transport and maintain the barrier's integrity.
Q.35Easy
Which of the following enzymes is responsible for breaking down acetylcholine at the neuromuscular junction?
Answer: A
Acetylcholinesterase rapidly hydrolyzes acetylcholine in the synaptic cleft, terminating neuromuscular transmission and allowing muscle relaxation.
Q.36Easy
The phenomenon where a nerve impulse can jump from one node of Ranvier to the next is called:
Answer: A
Saltatory conduction occurs in myelinated neurons where action potentials jump between nodes of Ranvier, increasing conduction velocity significantly compared to unmyelinated fibers.
Q.37Easy
Which structure in the kidney is responsible for ultrafiltration?
Answer: A
The glomerulus, a network of capillaries in the renal corpuscle, filters blood under hydrostatic pressure to produce the ultrafiltrate that forms the basis of urine.
Q.38Easy
Which of the following hormones is primarily responsible for increasing blood glucose levels during the fasting state?
Answer: A
Glucagon is secreted by alpha cells of pancreatic islets and increases blood glucose by promoting glycogenolysis and gluconeogenesis during fasting.
Q.39Easy
The sinoatrial (SA) node is considered the pacemaker of the heart because:
Answer: A
The SA node has the highest inherent rate of spontaneous depolarization (60-100 bpm), allowing it to set the rhythm for the entire heart.
Q.40Easy
Which of the following best describes the function of the loop of Henle in the kidney?
Answer: B
The loop of Henle, particularly the descending and ascending limbs, creates a countercurrent multiplier system that establishes an osmotic gradient necessary for concentrated urine formation.
