Homologous organs and Analogous organs.

Explanation

### Step-by-Step Solution

**1. Definition of Homologous Organs:**
- Homologous organs are those that have a similar internal structure and origin but may serve different functions. They arise from a common ancestor and exhibit variations in form and function due to adaptation to different environments.
- **Example:** The forelimb of humans, whales, and bats are homologous organs. They have similar bone structures but perform different functions (grasping, swimming, and flying, respectively).

**2. Definition of Analogous Organs:**
- Analogous organs are those that have similar functions and superficial appearances but differ in structure and origin. They do not arise from a common ancestor but evolve independently to adapt to similar environmental challenges.
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