Which comparison correctly distinguishes an organ from an organ system?
(a)An organ contains one tissue type; an organ system contains several tissue types.
(b)An organ combines tissues; an organ system combines interacting organs that perform a common function.
(c)An organ system is a larger tissue, while an organ is an arbitrary cell collection.
(d)An organ combines tissues; any nearby organs form an organ system without needing to interact.
Show answer
(b) An organ combines tissues; an organ system combines interacting organs that perform a common function.
An organ is formed from tissues in characteristic proportions and patterns and may contain several tissue types. An organ system contains organs that interact physically and/or chemically to perform a common function.
Question 2
What does morphology study in a frog?
(a)Structure of internal organs
(b)Externally visible appearance
(c)Functions of organs
(d)Development from tadpole to adult
Show answer
(b) Externally visible appearance
Morphology is the study of externally visible appearance in animals.
Frog adaptations and external morphology
Question 3
What is the function of the thin structure marked ? over the frog's eye?
(a)It receives sound signals from the surroundings.
(b)It produces the male frog's call.
(c)It protects the eye while the frog is in water.
(d)It absorbs water through the mouth.
Show answer
(c) It protects the eye while the frog is in water.
The nictitating membrane covers and protects the eye while the frog is in water. Sound signals are received by the tympanum beside the eye.
Question 4
Which comparison correctly links frog body temperature, water uptake and seasonal sheltering?
(a)Temperature varies with the environment; water is absorbed through skin; summer brings aestivation and winter hibernation.
(b)Temperature varies with the environment; water is absorbed through skin; summer brings hibernation and winter aestivation.
(c)Temperature stays constant; water is absorbed through skin; summer brings aestivation and winter hibernation.
(d)Temperature varies with the environment; water is taken in through the mouth; summer brings aestivation and winter hibernation.
Show answer
(a) Temperature varies with the environment; water is absorbed through skin; summer brings aestivation and winter hibernation.
A frog's body temperature varies with environmental temperature. It absorbs water through moist skin, aestivates during peak summer and hibernates during winter.
Frog reproduction, development and ecological role
Question 5
The lifecycle diagram hides the larval stage with ?. Which complete sequence restores the frog's source-stated development?
(a)External fertilisation in water -> tadpole -> adult frog without metamorphosis
(c)External fertilisation in water -> tadpole -> metamorphosis -> adult frog
(d)External fertilisation in water -> direct development into an adult frog
Show answer
(c) External fertilisation in water -> tadpole -> metamorphosis -> adult frog
Fertilisation is external in water. Development includes a tadpole larva, which undergoes metamorphosis to form the adult.
Question 6
Where do the vasa efferentia open in a male frog?
(a)Ureter before entering the kidney
(b)Oviduct
(c)Bidder's canal inside the kidney
(d)Bidder's canal outside the kidney
Show answer
(c) Bidder's canal inside the kidney
The vasa efferentia enter the kidney and open into Bidder's canal within it.
Question 7
A learner claims, 'Frog fertilisation is internal, development is direct, and frogs have no agricultural or ecological value.' Which revision is complete?
(a)Fertilisation is external in water; a tadpole undergoes metamorphosis into the adult; frogs have no agricultural or ecological value.
(b)Fertilisation is external in water; a tadpole undergoes metamorphosis into the adult; frogs eat insects, protect crops and occupy important food-chain and food-web links.
(c)Fertilisation is internal; a tadpole undergoes metamorphosis into the adult; frogs eat insects, protect crops and occupy food-chain and food-web links.
(d)Fertilisation is external in water; development proceeds directly to the adult; frogs eat insects, protect crops and occupy food-chain and food-web links.
Show answer
(b) Fertilisation is external in water; a tadpole undergoes metamorphosis into the adult; frogs eat insects, protect crops and occupy important food-chain and food-web links.
Fertilisation is external in water, and the tadpole metamorphoses into the adult. Frogs eat insects and protect crops, and they are important food-chain and food-web links.
Frog digestive system and nutrition
Question 8
The part marked ? in the frog's alimentary canal is short. Which fact about the frog explains this?
(a)It absorbs water through its skin
(b)It eats animals
(c)It eats plants
(d)It hibernates in winter
Show answer
(b) It eats animals
The marked coiled region is the intestine. The frog eats animals, such as insects, so its alimentary canal and intestine are relatively short. Water uptake through the skin and winter rest have no bearing on intestinal length.
Question 9
What is the function of the gall bladder in a frog?
(a)Storage of bile
(b)Absorption of digested food
(c)Digestion of proteins
(d)Production of bile
Show answer
(a) Storage of bile
The gall bladder stores bile. It does not produce bile.
Frog respiration and circulation
Question 10
The schematic combines the frog heart plan, its major entry and exit connections, and one portal route. Which interpretation is correct?
(a)The heart has two atria and one ventricle. The entry chamber is the sinus venosus, and the exit chamber is the conus arteriosus. The shown portal route is hepatic.
(b)The heart has two atria and two ventricles; the entry and exit identifications and the hepatic portal route are otherwise unchanged.
(c)The heart has three chambers, but the sinus venosus opens from the ventricle and the conus arteriosus joins the right atrium; the portal route is hepatic.
(d)The heart and its entry and exit chambers are identified correctly, but the intestine-to-liver route is the renal portal system.
Show answer
(a) The heart has two atria and one ventricle. The entry chamber is the sinus venosus, and the exit chamber is the conus arteriosus. The shown portal route is hepatic.
The frog heart has two atria and one ventricle. The sinus venosus receives vena-caval blood and joins the right atrium, the ventricle opens into the conus arteriosus, and the intestine-to-liver connection is the hepatic portal system.
Question 11
Which complete comparison of respiration in a frog is correct?
(a)Water—skin; land—buccal cavity, skin and lungs; aestivation or hibernation—no gaseous exchange.
(b)Water—skin; land—buccal cavity, skin and lungs; aestivation or hibernation—skin.
(c)Water—skin; land—lungs alone; aestivation or hibernation—skin.
(d)Water—lungs; land—buccal cavity, skin and lungs; aestivation or hibernation—skin.
Show answer
(b) Water—skin; land—buccal cavity, skin and lungs; aestivation or hibernation—skin.
In water, the frog uses its skin for cutaneous respiration. On land, the buccal cavity, skin and lungs participate, while during aestivation or hibernation gaseous exchange continues through the skin.
Frog neural, endocrine and sensory coordination
Question 12
In the lateral frog-head diagram, ? points to the flat membrane visible just behind the eye. Which identification and function statement is complete?
(a)It is the internal ear exposed at the body surface, and equilibrium is controlled only by the eye.
(b)It is the tympanum; no external ear is present, and the ear functions in hearing and equilibrium.
(c)It is the tympanum; no external ear is present, but the ear functions only in hearing.
(d)It is a visible external ear, which functions in hearing and equilibrium.
Show answer
(b) It is the tympanum; no external ear is present, and the ear functions in hearing and equilibrium.
The visible membrane is the tympanum; a projecting external ear is absent. The ear participates in hearing and equilibrium.
Question 13
How many pairs of cranial nerves arise from a frog's brain?
(a)Twelve
(b)Eight
(c)Ten
(d)Five
Show answer
(c) Ten
Ten pairs of cranial nerves arise from the frog's brain.
Frog excretion and cloacal pathways
Question 14
In this schematic, what is the function of the duct running from the kidney to the terminal chamber?
(a)Storing urine
(b)Producing urine
(c)Carrying urine to the cloaca
(d)Carrying ova
Show answer
(c) Carrying urine to the cloaca
The separate pathways identify a female frog. Its ureter carries urine to the cloaca, while the oviduct carries ova through a separate opening.
Question 15
Where does each oviduct open in a female frog?
(a)Ureter
(b)Cloaca
(c)Rectum
(d)Urinary bladder
Show answer
(b) Cloaca
Each oviduct in a female frog opens into the cloaca separately from the ureters.
Common misconception in Structural Organisation in Animals
The stomach is made entirely of muscle because it squeezes food.
Why it feels right. I identify it by its most visible action.
Right
An organ combines tissue types to perform several functions.
Worked example
Muscle
Contracts→Churns food
Epithelium
Faces stomach cavity→Lines and protects surface
Nerves
Carry signals→Help coordinate activity
Different tissues in the same organ contribute different functions.
Muscle helps churn food.
An epithelial lining faces the stomach cavity, and nerves help coordinate activity.
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