Questions About Crocodilia
Multiple-Choice Questions: Crocodilia
Structure, Physiology, Reproduction, Classification, and Ecology
1. Crocodilians are part of which class?
A) Amphibia
B) Mammalia
C) Reptilia
D) Osteichthyes
E) Aves
2. Which of the following is a distinguishing feature of crocodilians?
A) Four-chambered heart
B) Gills for respiration
C) Fur-covered body
D) External fertilization
E) Cartilaginous skeleton
3. Crocodilians regulate their body temperature through:
A) Internal heat production
B) Sweating
C) Ectothermy
D) Feathers
E) Mucous glands
4. Which of the following crocodilian species has the narrowest snout?
A) Nile crocodile
B) American alligator
C) Saltwater crocodile
D) Gharial
E) Dwarf caiman
5. What is the primary function of the nictitating membrane in crocodilians?
A) Aid in digestion
B) Assist in locomotion
C) Protect the eye underwater
D) Clean the skin
E) Detect vibrations
6. How do crocodilians primarily capture prey?
A) Using venom
B) Filtering through gills
C) Ambush and strong jaws
D) Climbing trees
E) Poisonous saliva
7. Which feature enables crocodilians to see, hear, and breathe while submerged?
A) Transparent skin
B) Lateral line system
C) Elevated eyes, ears, and nostrils
D) Bioluminescence
E) Spiracles
8. Crocodilians excrete nitrogenous waste mainly in the form of:
A) Urea
B) Ammonia
C) Uric acid
D) Protein
E) Nitrite
9. Crocodilians reproduce through:
A) Budding
B) Binary fission
C) Internal fertilization
D) External fertilization
E) Parthenogenesis
10. Crocodilian eggs are:
A) Soft, jellylike eggs laid in water
B) Shelled eggs laid on land
C) Fertilized externally in water
D) Developed internally and born live
E) Developed through mitosis only
11. The sex of crocodilian offspring is determined by:
A) Genetic inheritance
B) Random cell division
C) Environmental pollution
D) Temperature during incubation
E) Parental dominance
12. What is the name of the structure where crocodilian reproduction and excretion occur?
A) Trachea
B) Ovule
C) Cloaca
D) Rectum
E) Ureter
13. The order Crocodilia includes all of the following except:
A) Alligators
B) Caimans
C) Turtles
D) Gharials
E) Crocodiles
14. Which of the following is true about crocodilian parental care?
A) They abandon the nest after laying eggs
B) Males incubate the eggs
C) They show no parental care
D) Females guard the nest and help hatchlings
E) They feed their young with milk
15. Crocodilians first appeared during which geological period?
A) Cambrian
B) Devonian
C) Triassic
D) Cretaceous
E) Paleogene
16. Crocodilians are most closely related to which of the following?
A) Lizards
B) Frogs
C) Turtles
D) Birds
E) Mammals
17. What is a key difference between crocodiles and alligators?
A) Crocodiles live only in freshwater
B) Alligators have longer, sharper snouts
C) Alligator upper teeth are always visible
D) Crocodiles have a V-shaped snout, alligators U-shaped
E) Alligators have salt glands
18. Crocodilians primarily inhabit:
A) Deserts
B) Coral reefs
C) Forest canopies
D) Wetlands and rivers
E) Open oceans
19. The vocalization of young crocodilians is used to:
A) Defend territory
B) Communicate with fish
C) Attract mates
D) Signal the mother to help them hatch
E) Warn predators
20. What major threat affects crocodilian populations today?
A) Photosynthesis
B) Habitat destruction and illegal hunting
C) Excess oxygen
D) Lack of natural predators
E) Competition with birds
- Questions on Fish Reproduction, Classification, and Evolution
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Answer Key with Explanations
1. C) Reptilia – Crocodilians are reptiles.
2. A) Four-chambered heart – Unlike most reptiles, crocodilians have a fully divided heart.
3. C) Ectothermy – They depend on the environment for heat.
4. D) Gharial – Characterized by a very narrow, long snout for catching fish.
5. C) Protect the eye underwater – The nictitating membrane acts like goggles.
6. C) Ambush and strong jaws – Crocodilians ambush prey and use powerful bites.
7. C) Elevated eyes, ears, and nostrils – This adaptation helps while mostly submerged.
8. C) Uric acid – Like many reptiles, they excrete uric acid to conserve water.
9. C) Internal fertilization – Fertilization occurs inside the female’s body.
10. B) Shelled eggs laid on land – Eggs are leathery or calcified and laid in nests.
11. D) Temperature during incubation – Warmer or cooler temps determine sex.
12. C) Cloaca – A common chamber for excretion and reproduction.
13. C) Turtles – Turtles are reptiles but belong to the order Testudines.
14. D) Females guard the nest and help hatchlings – Crocodilian mothers are protective.
15. C) Triassic – Crocodilians evolved in the late Triassic, over 200 million years ago.
16. D) Birds – Birds and crocodilians share a common archosaur ancestor.
17. D) Crocodiles have a V-shaped snout, alligators U-shaped – A visible physical trait.
18. D) Wetlands and rivers – Their habitat includes freshwater and brackish environments.
19. D) Signal the mother to help them hatch – Hatchlings call for help from the mother.
20. B) Habitat destruction and illegal hunting – Major threats to their survival.
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