What is basic unit of classification?

What is basic unit of classification?

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Explanation

Species is the basic unit of classification.

Species are a group of organisms that are morphologically similar and can interbreed.

Classification system as proposed by Linnaeus 
These groups or levels are:
  1. Kingdom
  2. Phylum
  3. Class
  4. Order
  5. Family
  6. Genus 
  7. Species
Species is the smallest unit of classification.