which phylum has the least number of species?
a)porifera
b)coelenterata
c)platyhelminthes
d)nematoda
e)annelida
f)mollusca
g)arthropoda
h)enchinodermata
i)chordata

F) mollusca

"Mollusca is the second largest phylum of invertebrate animals. The members are known as molluscs or mollusks (/ˈmɒləsk/). Around 85,000 extant species of molluscs are recognized. The number of fossil species is estimated between 60,000 and 100,000 additional species."

A) porifera has the least number of species

i think the miocene epoch spans the time from 23 million to 12 million years ago.

the correct answer is d