# Regardin Assertion (A) and its Reason (R) :- A: Fishes, amphibians, reptiles, birds are placed in Phyllum Chordata but not mammals R: They are placed in a single phyllum based on the common features like presence of notochord and dorsal hollow neural system

( a ) A is incorrect but R is correct
( b ) Both A and R are correct but R is not the correct explanation for A
( c ) A is incorrect but R is correct; R is the correct explanation for A
( d ) A is correct but R is incorrect

Classes comprising animals like fishes, amphibians, reptiles, birds along with mammals constitute the next higher category called Phylum. All these, based on the common features like presence of notochord and dorsal hollow neural system, are included in phylum Chordata. In case of plants, classes with a few similar characters are assigned to a higher category called Division