Step 1: Characteristics of Pea Plants.
Mendel chose pea plants for his experiments because they have several distinct advantages:
1. Clear-cut Traits: Pea plants have easily distinguishable characteristics such as flower color, seed shape, and pod color.
2. Short Generation Time: They reproduce quickly, allowing Mendel to observe multiple generations in a short period.
3. Self-pollination: Pea plants can self-pollinate, ensuring that traits remain consistent unless cross-pollination is deliberately induced.
4. Ease of Cross-Pollination: Mendel could manually control the cross-pollination between different pea plants to study inheritance patterns.
Step 2: Conclusion.
Thus, the pea plant was an ideal model organism for studying the inheritance of traits, as it allowed Mendel to observe clear, predictable patterns of inheritance.
Final Answer:
\[
\boxed{\text{Mendel chose pea plants due to their clear-cut traits, short generation time, and ability to self-pollinate.}}
\]