In the developmental history of mammalian heart, it is observed that it passes through a two-chambered fish-like heart, three-chambered frog-like heart and finally four-chambered stage. To which hypothesis can this above cited statement be approximated

Options

A. Biogenetic law
B. Hardy-Weinberg law
C. Lamarck's principal
D. Mendelian principles

Answer

To solve the question regarding the developmental history of the mammalian heart and its relation to a specific hypothesis, we can follow these steps:

### Step 1: Understand the Developmental Stages of the Mammalian Heart
The question states that the mammalian heart develops through three stages:
- A two-chambered heart (fish-like)
- A three-chambered heart (frog-like)
- A four-chambered heart (mammalian)

### Step 2: Identify the Relevant Hypotheses
The question provides four hypotheses:
1. Biogenetic Law
2. Hardy-Weinberg Law
3. Lamarck's Principle
4. Mendelian Principle

### Step 3: Analyze Each Hypothesis
- **Biogenetic Law**: Proposed by Ernst Haeckel, it states that "ontogeny recapitulates phylogeny," meaning that the development of an individual organism (ontogeny) reflects the evolutionary history of its species (phylogeny). This law suggests that the embryonic development stages of an organism mirror the adult forms of its evolutionary ancestors.

- **Hardy-Weinberg Law**: This law pertains to genetic equilibrium in populations and does not relate to developmental biology.

- **Lamarck's Principle**: This principle discusses the inheritance of acquired traits, which is not relevant to the developmental stages of the heart.

- **Mendelian Principle**: This principle focuses on inheritance patterns in genetics and does not address the evolutionary development of structures.

### Step 4: Conclude the Correct Answer
Given that the developmental history of the mammalian heart reflects its evolutionary stages, the correct hypothesis that aligns with this observation is the **Biogenetic Law**.

### Final Answer
The correct answer is **Biogenetic Law**.

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