Drosophila has many types of hereditary variations that can be seen with low power microscopes.

Answer

### Step-by-Step Solution

1. **Understanding Drosophila melanogaster**:
- Drosophila melanogaster, commonly known as the fruit fly, is a model organism in genetics. It has a simple genetic structure and a short life cycle, making it ideal for genetic studies.

2. **Significance of Thomas Hunt Morgan**:
- Thomas Hunt Morgan was a pioneering geneticist who conducted extensive research on Drosophila melanogaster. He discovered the role of chromosomes in heredity and established the concept of sex-linked traits.

3. **Chromosomal Sex Determination**:
- In Drosophila, males have an XY chromosome configuration while females have an XX configuration. This chromosomal difference is crucial for understanding inheritance patterns.

4. **Types of Hereditary Variations**:
- Drosophila exhibits various hereditary variations (mutations) that can be observed under a microscope. Some notable mutations include:
- **B Mutation (Black)**:
- This mutation leads to the fruit fly having black wings, body, veins, and legs due to the inability to produce beta-alanine. It is an X-linked recessive mutation.
- **BW Mutation (Brown)**:
- In this mutation, the fruit fly cannot produce the pteridine pigment, leading to brown eyes instead of the typical red. This mutation is caused by a point mutation on chromosome 2.
- **W Mutation (White)**:
- This mutation results in white eyes due to the absence of both pteridine and omegrome pigments.

5. **Other Mutations**:
- Additional mutations include vestigial wing mutation (where the wings are reduced in size) and miniature wing mutation, which can also be observed under low power microscopes.

6. **Conclusion**:
- The statement that Drosophila has many types of hereditary variations that can be seen with low power microscopes is indeed true, as these mutations are prominent and easily identifiable.