Which of the following is correctly sequenced?

Options

A. Phylum, class, order, family
B. Phylum, order, class, genus
C. Phylum, class, family, order
D. Phylum, order, family, class

Answer

To determine which of the following sequences is correctly sequenced in the biological classification hierarchy, we need to understand the correct order of taxonomic ranks. The hierarchy of biological classification from the broadest to the most specific is as follows:

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

Now, let's analyze the options provided:

**Option A**: Phylum → Class → Order → Family
- This sequence is correct as it follows the proper order.

**Option B**: Phylum → Order → Class → Family
- This sequence is incorrect because it skips Class after Phylum.

**Option C**: Phylum → Class → Family → Order
- This sequence is incorrect because it places Family before Order, which is not the correct order.

**Option D**: Order → Class → Family
- This sequence is incorrect as it starts with Order and skips Phylum, and also places Class after Order, which is not correct.

Based on the analysis, the only correct sequence is **Option A**: Phylum → Class → Order → Family.

### Step-by-Step Solution:
1. **Understand the Taxonomic Hierarchy**: Familiarize yourself with the order of biological classification: Kingdom, Phylum, Class, Order, Family, Genus, Species.
2. **Analyze Each Option**: Go through each option one by one to check if they follow the correct sequence.
3. **Identify the Correct Option**: Determine which option maintains the correct order without skipping any ranks or reversing them.
4. **Select the Correct Answer**: Conclude that Option A is the only correct sequence.