In 2000, maize hybrids that had twice the amount of the amino acids_______and_______, compared to existing maize hybrids were developed.

Answer

To answer the question regarding the maize hybrids developed in 2000, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks for two specific amino acids that were increased in quantity in maize hybrids developed in the year 2000.

2. **Identify the Context**: The context of the question relates to advancements in agricultural biotechnology, specifically the development of maize hybrids that are nutritionally enhanced.

3. **Recall Relevant Information**: From the study of amino acids, we know that certain amino acids are classified as essential, meaning they cannot be synthesized by the body and must be obtained through diet.

4. **Focus on Maize Hybrids**: In the context of maize, it is known that researchers have worked on enhancing the nutritional profile of maize by increasing the levels of certain essential amino acids.

5. **Identify the Amino Acids**: The two essential amino acids that were specifically mentioned in the context of maize hybrids developed in 2000 are **lysine** and **tryptophan**. These amino acids are important for human nutrition and were increased to improve the overall quality of maize as a food source.

6. **Fill in the Blanks**: Therefore, the answer to the question is:
- In 2000, maize hybrids that had twice the amount of the amino acids **lysine** and **tryptophan**, compared to existing maize hybrids were developed.

### Final Answer:
In 2000, maize hybrids that had twice the amount of the amino acids **lysine** and **tryptophan** compared to existing maize hybrids were developed.

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