The lowest unit of classification is the

1. Analyze the question The question asks for the lowest (most specific) rank in the hierarchy of biological classification (taxonomy).

2. Explain the concept Living organisms are grouped from the broadest category down to the most specific one:

Kingdom → Phylum → Class → Order → Family → Genus → Species

• Moving down, the groups get smaller and members share more characteristics.
• Moving up, the groups get larger and members share fewer characteristics.

3. Step-by-step solution

• Class is in the upper-middle part of the hierarchy, so it is not the lowest.
• Genus is lower than class, but it still contains one or more species.
• Phylum is near the top, just below kingdom, so it is very broad.
• Species is the last rank. It is a group of organisms that can interbreed and produce fertile offspring. For example, Homo sapiens is the species of humans.

4. Answer The lowest unit of classification is the species, which is option D.

5. Exam tip Use this mnemonic to remember the order from top to bottom: "King Philip Came Over For Good Soup" (Kingdom, Phylum, Class, Order, Family, Genus, Species). The last word, Soup, stands for Species, the lowest rank. If a JAMB question asks for the "highest" rank, the answer is kingdom. If it asks for the "lowest", the answer is species.