Question

Zonary placenta is found in
A. Carnivore mammals
B. Herbivore mammals
C. Crow
D. Both A and B

Answer 1

Hint: Carnivores like cats and dogs have zonary placenta. Herbivores like elephants also have zonary placenta. Crows are birds that develop from an egg and do not have a placenta.

Complete answer:
Mammals, barring a few exceptions (like the monotremes such as duck billed platypus), are viviparous animals. In viviparous animals, the embryo develops within the body of one parent during a species- specific time called gestation and after gestation live animals are born.

Placenta is a temporary organ developed in the uterus of all eutherian mammals. Placenta functions to deliver nutrients and protective immunoglobulin to the developing foetus and also function to remove waste products such as uric acid utilising the maternal blood circulation.

There are different types of placenta based on the shape and contact points between the mother and the foetus.
These are cotyledonary, diffuse, discoid, and zonary types of placenta.
Diffuse placenta is found in animals like pigs and horses
Discoid type of placenta is seen in primates including humans.
Cotyledonary placenta is found in ruminant animals like sheep, goat, and cattle. In this type of placenta, the maternal endometrium makes multiple discrete contact points with allantochorion.
Zonary placenta forms as a band surrounding the developing foetus. This type of placenta is found in carnivores like dogs, cats, seals, omnivores like bears and herbivores like elephants.

Hence the correct answer is OPTION(D)

Note: Zonary placenta classification is based on the type of contacts between the maternal and foetal membrane. This is not a distinguishing feature between carnivores and herbivores and is found in both types of animals