What is the smallest taxonomic group that contains organisms of a different species? a. genus b. order c. family d. domain

In hierarchical classification there are several categories: each category may include different taxa. Genus is the lowest category that includes different species.

Answer: Option A Genus

Explanation:

There are 8 different taxonomic groups that are used to group the organisms. These are- Domain, Kingdom, Phylum, Class, Order, Family, Genus, and Species.Domain is the broadest of all categories and the three domains of life are bacteria, archaea and eukaryota.After domain, the next category for grouping organisms is the kingdom. After kingdom, the next category is the phylum. It is again a very broad category however, not as broad as the kingdom category. For e.g all vertebrates are classified into a single phylum known as chordata.The next level is the class, for e.g in the phylum chordata we have class mammalia which includes all the mammals.After class the organisms are then divided into order and then further narrowed down to family. For e.g humans belong to class mammalia, order primates and family Hominidae.The final category is the genus and species which are used in binomial nomenclature to name an organism, for e.g humans are called as Homo sapiens where Homo is the genus and sapiens is the species.Thus, to classify human beings we get the general classification as:

Domain: Eukaryota

Kingdom: Animalia

Phylum: Chordata

Class: Mammalia

Order: Primates

Family: Hominidae

Genus: Homo

Species: Homo sapiens

Thus, we can see that from the given options the smallest taxonomic group that contains organisms of a different species is the genus because as we move down the hierarchy the number of organisms in each group decreases.