Which of the following characteristic features always holds true for the corresponding group of animals?

a)
3-chambered heart with one incompletely divided ventricle --- Reptilia

b)
Cartilaginous endoskeleton --- Chondrichthyes

c)
Viviparous --- Mammalia

d)
Possess a mouth with an upper and lower jaw --- Chordata

Correct answer is option 'B'. Can you explain this answer?

Question

Which of the following characteristic features always holds true for the corresponding group of animals?

a)
3-chambered heart with one incompletely divided ventricle --- Reptilia
b)
Cartilaginous endoskeleton --- Chondrichthyes
c)
Viviparous --- Mammalia
d)
Possess a mouth with an upper and lower jaw --- Chordata

Correct answer is option 'B'. Can you explain this answer?

Answer

---)¥ Chondrichthyes has endoskeleton made up of cartilage.

---€All Mammals are Viviparous except platypus which is Oviparous.

---->All Chordates posses a mouth with an upper and a lower jaw except agnatha which are without jaws.

•••••》All reptiles have 3 - chambered heart except crocodile and tortoise in which heart is four chambered but with an incomplete wall in the single ventricle, so their hearts are functionally 4 chambered.

Answer

2

Answer

Crocodile has 4 chambered heart though it comes under reptiles. Oviparous mammals are also found eg: ornithorhynchus (platypus). jawless vertebrates (agnatha) also comes under chordata.but all chondrichthyes have cartilaginous endoskeleton. therefore option 2 is correct.

Answer

Characteristic features of the corresponding groups of animals:

a) 3-chambered heart with one incompletely divided ventricle - Reptilia:
- Reptiles, including snakes, lizards, turtles, and crocodiles, have a 3-chambered heart with one incompletely divided ventricle.
- This means that their heart has two atria and one ventricle, but the ventricle is not completely separated into two chambers.
- As a result, oxygenated and deoxygenated blood mix to some extent in the ventricle, reducing the efficiency of oxygen delivery to the body tissues.
- This characteristic is one of the defining features of the reptilian group.

b) Cartilaginous endoskeleton - Chondrichthyes:
- Chondrichthyes, commonly known as cartilaginous fish, have a cartilaginous endoskeleton.
- Unlike bony fish, which have a skeleton made of bone, cartilaginous fish have a skeleton made of cartilage.
- Cartilage is a flexible and lightweight tissue that provides support and structure to the body.
- This characteristic allows cartilaginous fish, such as sharks and rays, to be more agile and maneuverable in water compared to bony fish.
- The cartilaginous endoskeleton also provides some degree of protection against predators and allows for a more streamlined body shape.

c) Viviparous - Mammalia:
- Mammals, including humans, dogs, cats, and whales, are viviparous, which means they give birth to live young.
- In viviparous animals, the offspring develop within the mother's body and are nourished by a placenta or other specialized structures.
- This allows for internal fertilization and provides a more controlled and protected environment for the developing embryo.
- Viviparity is a unique characteristic of mammals and is associated with the presence of mammary glands for milk production, which is used to nourish the newborns.

d) Possess a mouth with an upper and lower jaw - Chordata:
- Chordates, a diverse group of animals that includes vertebrates and some invertebrates, possess a mouth with an upper and lower jaw.
- This characteristic is one of the defining features of the chordate group.
- The presence of jaws allows chordates to have a more efficient and specialized feeding mechanism, enabling them to capture and process a wide variety of food sources.
- Jaws are derived from the modification of the skeletal elements that support the gill arches in ancestral chordates.

In conclusion:
- The correct answer to the question is option 'B' - Cartilaginous endoskeleton is a characteristic feature that always holds true for the group Chondrichthyes, which includes cartilaginous fish like sharks and rays.
- The other characteristic features mentioned are true for different groups of animals, but not necessarily for all members of those groups.

Answer

Reptilia has an order crocodilia which shows 4 chambered heart.

In mammals, prototheria group shows oviparity while metatheria & eutheria show viviparity.

Chordates can be gnathostomata & agnatha (without jaws).

Only cartilaginous fishes (chondrichthyes) show cartilaginous endoskeleton without exception

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