Understanding Taxonomic Ranks and Hierarchy

In biology, living organisms are classified into different groups based on their similarities and differences. This system of classification is called taxonomy, and the different levels of classification are known as taxonomic ranks.

The standard taxonomic hierarchy consists of several ranks arranged in a specific order, from the broadest category to the most specific. The generally accepted order, from highest (broadest) to lowest (most specific), is:

• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

The question asks for the descending hierarchy (from broadest to most specific) using a given set of taxonomic ranks and their corresponding codes:

• A. Order
• B. Genus
• C. Class
• D. Species
• E. Family

Determining the Descending Order of Taxonomic Ranks

Let's arrange the given ranks in descending order according to the standard taxonomic hierarchy:

1. Class: This is a higher rank than Order, Family, Genus, and Species. (Code C)
2. Order: This rank is below Class but above Family, Genus, and Species. (Code A)
3. Family: This rank is below Order but above Genus and Species. (Code E)
4. Genus: This rank is below Family but above Species. (Code B)
5. Species: This is the most specific rank among the given options. (Code D)

So, the descending order of the given taxonomic ranks is:

Class > Order > Family > Genus > Species

Mapping Ranks to Codes for the Final Sequence

Now, let's map the codes to this descending sequence:

• Class is Code C
• Order is Code A
• Family is Code E
• Genus is Code B
• Species is Code D

Therefore, the descending hierarchy using the given codes is CAEBD.