D. Ecosystems are important in maintaining the good chain among all the organisms within it, which contributes to a high value of biodiversity
Answer:
controlled the fertilization process.
Explanation:
Mendel took precautions to avoid contamination by pollen through self pollination of the P generation. He controlled the fertilization processes between the plants. He self pollinated the first pureline varieties to form the P generation. He then cross pollinated them to get F1 generation. Every step of his experiment was controlled.