Fruit flies are one of the best materials for genetic studies because of all , except

Options

A. Ability to grow on simple synthetic medium in the laboratory
B. Short life span
C. Production of a large number of progeny in each mating
D. Presence of few externally visible and identifiable contrasting traits

Answer

**Step-by-Step Solution:**

1. **Identify the Subject**: The question pertains to the genetic studies involving fruit flies, specifically Drosophila melanogaster, which are widely used in genetics research.

2. **Understand the Context**: Thomas Hunt Morgan is a key figure in genetics who used fruit flies for his experiments. He is known for his work on inheritance patterns and genetic linkage.

3. **List the Advantages of Using Fruit Flies**:
- They can grow on a simple synthetic medium, feeding on yeast.
- They have a short lifespan, allowing for quick generation turnover (progeny can be raised in about two weeks).
- They produce a large number of progeny in each mating, facilitating statistical analysis of genetic traits.

4. **Analyze the Options**: The question asks for the exception among the advantages listed. The options likely include the three advantages mentioned above and one incorrect statement.

5. **Identify the Incorrect Statement**: The fourth option states that fruit flies have "few externally visible and identifiable contrasting characters." This is incorrect because fruit flies actually have many identifiable traits, such as eye color, wing shape, and body color, which can be easily observed.

6. **Conclude the Answer**: The correct answer to the question, which identifies the exception, is the fourth option regarding the presence of few identifiable contrasting characters.

**Final Answer**: The fruit flies are one of the best materials for genetic studies because all of these except the presence of few externally visible and identifiable contrasting characters.

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