Vertebrate hearts and brains shows

Options

A. analogy
B. atavism
C. homology.
D. adaptive radiation

Answer

### Step-by-Step Solution:

1. **Understanding the Terms:**
- First, we need to clarify the terms used in the question: analogy, homology, atavism, and adaptive radiation.

2. **Analogy:**
- Analogous organs are those that have different structures but perform the same function. For example, the wings of bats and birds are analogous; they serve the same purpose (flight) but have different anatomical structures.

3. **Homology:**
- Homologous organs have the same basic anatomical structure but may serve different functions. For instance, the forelimbs of bats and humans are homologous; they share a similar bone structure (humerus, radius, and ulna) but are used for different purposes (flight vs. manipulation).

4. **Vertebrate Hearts:**
- When considering vertebrate hearts, both fish (Pisces) and mammals have a similar basic structure (auricles and ventricles). However, they perform different functions: fish exhibit single circulation, while mammals and birds have double circulation.

5. **Vertebrate Brains:**
- Similarly, vertebrate brains also show homology. They share a common structural plan but may have evolved to perform different functions in different species.

6. **Conclusion:**
- Therefore, the correct answer to the question "Vertebrate hearts and brains show" is that they exhibit **homology**.