Question

Double uterus and double vagina are characteristic of
A. Prototheria
B .Metatheria
C. Chiroptera
D. Cetacea

Answer 1

Hint: Classification of animals is based on their specific characters and unique characters. Kingdom Animalia is broadly classified into two phylum Invertebrates and Vertebrates. A phylum Vertebrata is further subdivided into 5 class namely Pisces, Amphibians, Reptiles, Birds, and Mammals. Class Mammalia is further sub-divided into 3 sub-classes are Prototheria, Metatheria, and Eutheria.

Complete answer: All the mammals have the presence of mammary glands but based on a few notable differences this class is subdivided into 3 sub-classes Prototheria, Metatheria, and Eutheria.
Prototheria are egg-laying mammals. Examples: Platypus, Echidna. Metatheria includes pouch bearing mammal Examples: Kangaroo, Opossum. Eutheria includes mammals having placenta, for example Humans, Bats.

Prototheria	Metatheria	Eutheria
They are oviparous animals.(produce young ones by laying eggs)	They are viviparous animals.(produce young ones by live birth)	They are viviparous animals.(produce young ones by live birth)
The ears lack pinna.	They have ear pinna.	They have ear pinna aquatic forms that are an exception to this.
Vagina and uterus are absent.	Double vagina and double uterus present.	One vagina and one uterus present.
Nipples are absent on the mammary gland.	Nipples are present.	Nipples are present.

So, Hence the correct answer is option B-Metatheria. The presence of a double vagina and double the uterus is a characteristic feature of mammalian subclass Metatheria.

Note: Bat is the only flying mammal that is often misunderstood as a bird. Sub-class prototheria has only one living order monotreme with just five living species. Marsupials are pouch bearing mammals, pouches are meant for young ones' development. Eutherians have a placenta meant for providing oxygen and nutrients to the growing embryo. Placenta also helps in the removal of waste from a foetus's body.