On what basis the concept of common ancestor was given?

Explanation

**Step-by-Step Solution:**

1. **Understanding the Concept of Common Ancestor:**
- The concept of a common ancestor refers to the idea that different species have evolved from a shared ancestral species. This is a fundamental principle in the study of evolution.

2. **Evolutionary Relationships:**
- The common ancestor concept helps in understanding the evolutionary relationships among various organisms. It suggests that all living organisms share a common lineage, which has diverged over time into different species.

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