Mendel selected seven visible characters each with two contrasting traits.

Answer

**Step-by-Step Text Solution:**

1. **Introduction to Mendel's Work**: Gregor Mendel is known as the father of genetics. He conducted experiments on pea plants to understand the principles of inheritance.

2. **Selection of Characters**: Mendel selected seven visible characters in pea plants, each with two contrasting traits. This means for each character, one trait is dominant and the other is recessive.

3. **List of Characters and Their Traits**:
- **1. Pea Shape**: Round (dominant) vs. Wrinkled (recessive)
- **2. Pea Color**: Yellow (dominant) vs. Green (recessive)
- **3. Pod Shape**: Inflated (dominant) vs. Constricted (recessive)
- **4. Pod Color**: Yellow (dominant) vs. Green (recessive)
- **5. Flower Color**: Purple (dominant) vs. White (recessive)
- **6. Plant Size**: Tall (dominant) vs. Dwarf (recessive)
- **7. Position of Flower**: Axial (dominant) vs. Terminal (recessive)

4. **Conclusion**: Mendel's selection of these seven characters with contrasting traits allowed him to establish the fundamental laws of inheritance, confirming the statement in the question is true.

---