Part 6 — Amphibia, Reptilia, Aves & Mammalia (Q.126–150)

Part 6 — Amphibia, Reptilia, Aves & Mammalia (Q.126–150)

Q126. Amphibians are called “double life” animals because:

A) They live twice the lifespan of reptiles
B) They have aquatic larval stage (gilled) and terrestrial adult stage (lunged), requiring moist habitats for reproduction
C) They can fly and swim equally well
D) They are terrestrial only
Answer: B
Explanation:
A/C/D) Incorrect.
B) Correct — typical amphibian life cycle.

Q127. Which of the following is a unique feature of amphibian skin?

A) Dry and scaly
B) Permeable, glandular (mucous and poison glands), assists in cutaneous respiration
C) Covered with feathers
D) Covered with fur
Answer: B
Explanation:
A) Scales in reptiles.
B) Correct — amphibian skin moist and glandular.
C/D) Bird/mammal traits.

Q128. Reptiles differ from amphibians by:

A) Laying eggs in water only
B) Having dry scaly skin, amniotic egg, internal fertilization, better adaptation to terrestrial life
C) Requiring larval metamorphosis always
D) Lack of lungs
Answer: B
Explanation:
A/C/D) Incorrect.
B) Correct — reptiles are amniotes with terrestrial adaptations.

Q129. The amniotic egg contains which membranes?

A) Only chorion
B) Chorion, amnion, yolk sac, and allantois — adaptations for terrestrial development: amnion cushions, allantois for waste storage, chorion for gas exchange
C) Only shell and embryo
D) No membranes
Answer: B
Explanation:
A/C/D) Incomplete.
B) Correct — full set of extraembryonic membranes in amniotes.

Q130. Birds (Aves) are distinguished by:

A) Presence of feathers, forelimbs modified into wings, hollow bones, high metabolic rate and four-chambered heart
B) Scaly skin and cold-blooded metabolism
C) Live birth and hair
D) No vertebral column
Answer: A
Explanation:
B) Reptiles.
C) Mammals.
D) False.
A) Correct — key avian characters.

Q131. Endothermy (warm-bloodedness) is characteristic of:

A) Amphibians
B) Reptiles
C) Birds and mammals — maintain internal temperature via metabolic heat (endothermy) and insulation (feathers/fur)
D) Fish
Answer: C
Explanation:
A/B/D) Ectothermic mostly.
C) Correct.

Q132. Which of the following classes has a four-chambered heart?

A) Amphibia (three-chambered generally)
B) Reptilia (three-chambered except crocodiles), Aves and Mammalia have fully four-chambered hearts
C) Fish only
D) Invertebrates
Answer: B
Explanation:
A) Amphibians have 3-chambered heart (except some variations).
B) Correct — birds and mammals; crocodiles among reptiles have four chambers.
C/D) Not accurate.

Q133. Reptilian skin contains:

A) Mucous glands primarily
B) Keratinized scales to reduce water loss and protect from desiccation
C) Feathers
D) Hair
Answer: B
Explanation:
A) Amphibians have mucous glands.
B) Correct — reptile epidermis with keratin scales.
C/D) Birds/mammals.

Q134. Ovoviviparity (eggs hatch within mother and young are born live) is seen in:

A) Some reptiles (e.g., many snakes), and in some fishes and invertebrates but not predominant in birds or mammals
B) All birds
C) All amphibians
D) All mammals
Answer: A
Explanation:
B/C/D) Incorrect generalizations.
A) Correct — ovoviviparity occurs in some reptiles and fishes.

Q135. The feathers of birds are modified:

A) Scales from reptilian ancestors (epidermal derivatives) adapted for flight, insulation, and display
B) Hair follicles
C) Glands
D) Teeth
Answer: A
Explanation:
B/C/D) Wrong.
A) Correct — feathers are modified scales.

Q136. Mammary glands are a defining characteristic of mammals and function in:

A) Respiration
B) Lactation — production of milk to feed young, a mammalian synapomorphy
C) Photosynthesis
D) Excretion
Answer: B
Explanation:
A/C/D) Not true.
B) Correct.

Q137. Which mammalian subclass gives birth to undeveloped young in a pouch (marsupium)?

A) Eutheria
B) Metatheria (Marsupials like kangaroo and opossum) — give birth to altricial young that complete development in pouch
C) Monotremata
D) Aves
Answer: B
Explanation:
A) Eutherians are placental mammals.
B) Correct.
C) Monotremes lay eggs.
D) Birds.

Q138. Monotremes (e.g., platypus) are unique among mammals because they:

A) Lay eggs and have mammary glands but no nipples (milk secreted onto skin/fur)
B) Are reptiles
C) Are birds
D) Are amphibians
Answer: A
Explanation:
B/C/D) Incorrect.
A) Correct — monotremes are egg-laying mammals.

Q139. In birds, the presence of air sacs function to:

A) Store food only
B) Ensure unidirectional airflow through lungs for efficient gas exchange — supporting high metabolic rate and flight
C) Reproduction exclusively
D) Produce feathers
Answer: B
Explanation:
A/C/D) Not accurate.
B) Correct.

Q140. Reptiles are mainly ectothermic, meaning:

A) They rely on external heat sources to regulate body temperature and behaviorally thermoregulate (basking)
B) They internally regulate temperature by metabolism (endothermy)
C) They Photosynthesize to produce heat
D) They use feathers to maintain warmth
Answer: A
Explanation:
B) Birds and mammals are endothermic.
A) Correct.

Q141. Altricial vs precocial young: which is true?

A) Altricial young are born/hatched helpless and require parental care (e.g., many passerines), precocial are relatively mature and mobile (e.g., ducks)
B) Altricial are fully independent immediately
C) Precocial are always parasitic
D) Both terms refer to egg shell types
Answer: A
Explanation:
B/C/D) Incorrect.
A) Correct.

Q142. The placenta in eutherian mammals functions to:

A) Exchange nutrients, gases and wastes between maternal and embryonic blood while providing hormonal support and immune protection
B) Produce eggs only
C) Generate flight muscles
D) Act as respiratory organ for adults
Answer: A
Explanation:
B/C/D) Not accurate.
A) Correct — placenta mediates maternal-fetal exchange.

Q143. Which of the following birds is flightless but evolved from flying ancestors?

A) Ostrich, emu — ratites are flightless birds adapted to running, with reduced wing structures
B) Eagle
C) Sparrow
D) Pigeon
Answer: A
Explanation:
B/C/D) Flying birds.
A) Correct.

Q144. Which mammalian order is characterized by flying mammals?

A) Chiroptera (bats) — only true flying mammals with membranous wings formed by forelimb elongation
B) Primates
C) Rodentia
D) Carnivora
Answer: A
Explanation:
B/C/D) Not flying.
A) Correct.

Q145. Which adaptation in mammals permits endothermy?

A) Feathers only
B) High metabolic rate, insulated fur/hair, developed lungs and structural modifications for efficient circulation and respiration
C) Scales only
D) Exoskeleton
Answer: B
Explanation:
B) Correct — combination of physiology and insulation supports thermoregulation.
A/C/D) Not mammalian-only adaptations.

Q146. The evolution of a four-chambered heart allowed:

A) Mixing of oxygenated and deoxygenated blood
B) Complete separation of pulmonary and systemic circulation allowing higher metabolic rates and endothermy in birds and mammals
C) Loss of lungs
D) Reduced blood pressure
Answer: B
Explanation:
A) Occurs in 3-chambered hearts (mixing).
B) Correct — four-chambered heart prevents mixing.
C/D) Incorrect.

Q147. Which reptile has a fully four-chambered heart like birds and mammals?

A) Snakes only
B) Crocodilians (crocodiles and alligators) have a 4-chambered heart, convergently evolved with birds/mammals for efficient circulation
C) Turtles only
D) All lizards
Answer: B
Explanation:
A/C/D) Most reptiles have a 3-chambered heart; crocodilians are an exception.
B) Correct.

Q148. The earliest amniotes gave rise to which major groups?

A) Only fish
B) Synapsids (leading to mammals) and sauropsids (leading to reptiles and birds) — two major amniote lineages
C) Plants
D) Protozoa
Answer: B
Explanation:
A/C/D) Not relevant.
B) Correct.

Q149. Which adaptation is absent in amphibians but present in reptiles and mammals?

A) Hinged jaws
B) Amniotic egg allowing embryonic development independent of water — reptiles and mammals are amniotes, amphibians are not
C) Vertebral column
D) Paired appendages
Answer: B
Explanation:
A/C/D) Present in various vertebrates.
B) Correct.

Q150. Which of the following pairs is correct regarding integument coverings?

A) Mammals — feathers; Birds — hair
B) Birds — feathers; Mammals — hair/fur; Reptiles — scales; Amphibians — moist glandular skin
C) Fish — hair; Amphibians — feathers
D) Reptiles — fur
Answer: B
Explanation:
A/C/D) Incorrect swaps.
B) Correct mapping of integumentary coverings. (more…)