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Zoology Past Paper MCQs
Zoology 2025 MCQs
1 / 20
The time delay between habitat fragmentation and the decline in species richness to equilibrium is called:
Relaxation time describes the lag before species numbers stabilize post-fragmentation. Retention time (C) is unrelated, and fragment destruction (A) is not a scientific term.
2 / 20
Erythropoietin, the hormone stimulating RBC production, is primarily synthesized by the:
The kidneys produce erythropoietin in response to low oxygen. The liver (A) contributes minimally in adults.
3 / 20
Crustaceans typically have blue blood due to:
Hemocyanin, a copper-based protein, gives crustacean blood its blue color. Hemoglobin (A) is iron-based and red.
4 / 20
An important intestinal fluke affecting large animals is:
Nanophyetus is a fluke parasitizing animals like dogs. Fasciola (A) infects the liver, and Schistosoma (C) causes human schistosomiasis.
5 / 20
When ecologically linked species evolve reciprocal selective pressures, it is called:
Coevolution occurs when species influence each other’s evolution (e.g., pollinators and flowers). Mutualism (C) is a type of interaction.
6 / 20
Prader - Willi syndrome results from a heterozygous deletion on the long arm of chromosome:
Prader-Willi is caused by a deletion on chromosome 15q11-q13. Chromosomes 5 (A) and 3 (C) are unrelated.
7 / 20
Which monosaccharide is absorbed in the intestine without requiring sodium ions?
Fructose is absorbed via facilitated diffusion, independent of sodium ions. Glucose (B) and galactose (C) require sodium-dependent transporters (SGLT1).
8 / 20
In chordate embryos, the notochord is eventually replaced by the:
The notochord is a flexible rod in embryos that is replaced by bony vertebrae in vertebrates. The nerve cord (A) persists as the spinal cord.
9 / 20
Which statement about animal behavior is TRUE?
Learning shapes behavior. Identical behavior (B) is false due to individual variation.
10 / 20
The autonomic nervous system regulates homeostasis through:
The ANS controls involuntary functions (e.g., heartbeat, digestion). External processes (B) involve somatic nerves.
11 / 20
Biodiversity measured at a large geographic scale is termed:
Gamma diversity refers to biodiversity across a landscape or region. Alpha diversity (B) is local (within a habitat), and beta diversity (A) compares diversity between habitats.
12 / 20
Frogs and salamanders belong to the class:
Amphibians live in water and land. Reptilia (A) includes snakes, and Mammalia (C) includes humans.
13 / 20
Iron - containing pigments in animals include:
Hemoglobin (B) carries oxygen in blood, and myoglobin (A) stores oxygen in muscles—both contain iron.
14 / 20
In pigeons, pigeon’s milk is produced by the:
The crop secretes a nutrient-rich slurry to feed chicks. The proventriculus (A) is the glandular stomach.
15 / 20
All of the following statements regarding “lung ventilation” and “gas exchange” are TRUE EXCEPT:
Birds use parabronchi (not alveoli) for gas exchange. Alveoli (B) are mammalian structures.
16 / 20
The process by which a caterpillar transforms into a butterfly is called:
Metamorphosis is the biological process where an organism undergoes a dramatic change in body structure, such as a caterpillar becoming a butterfly. Fragmentation (A) refers to asexual reproduction, and budding (B) is another form of asexual reproduction seen in organisms like yeast.
17 / 20
Diurnal animals are active:
Diurnal animals (e.g., humans) are day-active. Nocturnal (A) animals are night-active.
18 / 20
The biome with the highest annual precipitation is the:
Tropical rainforests receive >200 cm/year. Grasslands (B) and tundra (C) are drier.
19 / 20
Buoyancy in fish is primarily maintained by the:
The swim bladder adjusts gas volume to control buoyancy. Scales (B) and fins (C) aid in protection/movement.
20 / 20
Which of the following is NOT a coenzyme involved in pyruvic acid’s oxidative decarboxylation?
Biotin is a coenzyme for carboxylation reactions, not decarboxylation. CoA-SH (A) and Mg²⁺ (B) are essential for pyruvate dehydrogenase complex activity.
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