A ........... was utilised by Mendel which had undergone .......... for several generations.

Options

A. Hybridisation, Cross-pollination
B. Cross-breeding, Cross-pollination.
C. True breeding, autogamy.
D. Artificial Hybridisation

Explanation

**Step-by-Step Solution:**

1. **Identify the Organism Used by Mendel**: Mendel utilized the pea plant (Pisum sativum) for his experiments. This plant was chosen due to its distinct traits and ease of observation.

2. **Understand the Concept of Generations**: The term "generations" refers to the successive breeding of the plants. Mendel worked with plants that had undergone self-pollination for several generations to ensure that the traits were stable and pure.

3. **Define the Terms**:
- The first blank should be filled with "pea plant."
- The second blank should be filled with "self-pollination" or "autogamy," which refers to the process where pollen from the same flower fertilizes the ovules of that flower.

4. **Final Answer Construction**:
- The complete sentence would read: "A pea plant was utilized by Mendel which had undergone self-pollination for several generations."

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