Correct Option: A. Genus Detailed Explanation: In biological classification, organisms are categorized into a hierarchical system known as taxonomy. This system organizes living things into groups based on shared characteristics and evolutionary relationships. The main taxonomic ranks, from the broadest to the most specific, are as follows:

1. Domain
2. Kingdom
3. Phylum
4. Class
5. Order
6. Family
7. Genus
8. Species

In this hierarchy, each rank represents a level of classification. The rank of family is a grouping of related genera (plural of genus), and it is immediately followed by the rank of genus.

• Family: This rank groups together related genera that share certain characteristics. For example, the family Felidae includes all cats, such as lions, tigers, and domestic cats.
• Genus: This rank is one step below family and includes species that are closely related and share a common ancestor. For instance, within the family Felidae, the genus Panthera includes big cats like lions (Panthera leo) and tigers (Panthera tigris).

Thus, the correct answer to the question is A. Genus, as it is the taxonomic rank that comes immediately after family. Why Other Options Are Incorrect:

• B. Order: This rank is above family in the taxonomic hierarchy. For example, the order Carnivora includes families such as Felidae (cats) and Canidae (dogs). Therefore, order cannot come after family; it precedes it.
• C. Species: This rank is below genus in the hierarchy. A species is the most specific level of classification and refers to a group of individuals that can interbreed and produce fertile offspring. For example, within the genus Panthera, the species Panthera leo refers specifically to lions. Thus, species cannot come after family; it comes after genus.
• D. Class: This rank is also above family in the hierarchy. For example, the class Mammalia includes all mammals, which are further divided into orders, families, genera, and species. Therefore, class cannot come after family; it is a broader category.

Summary of Key Points:

• The taxonomic hierarchy is structured from broad to specific: Domain > Kingdom > Phylum > Class > Order > Family > Genus > Species.
• The rank that comes immediately after family is genus.
• Order and class are higher ranks than family, while species is a lower rank than genus.
• Understanding the hierarchy is crucial for classifying and identifying organisms accurately.

This structured approach to taxonomy helps biologists communicate about species and their relationships effectively, ensuring clarity in the study of biodiversity.