More than six hundred million tons of rice were grown around the world...
Explanation:
The correct answer is option D, "on the other hand".
Reasoning:
The sentence states that more than six hundred million tons of rice were grown around the world last year. However, it also implies that despite this large production, current rice production levels will not meet the needs of a growing world population twenty-five years from now.
To express this contrast or contradiction, the phrase "on the other hand" is used. This phrase is commonly used to introduce an opposing or contrasting point of view. In this case, it is used to highlight the fact that although a significant amount of rice was grown, it will not be sufficient to meet the future demands of the growing world population.
Example:
Let's consider an example to illustrate the use of "on the other hand" in a similar context:
"John is a talented musician. On the other hand, he lacks confidence when performing in front of large audiences."
In this example, the phrase "on the other hand" is used to introduce a contrasting statement. It acknowledges John's talent as a musician but highlights his lack of confidence when performing in certain situations. Similarly, in the given sentence about rice production, the phrase "on the other hand" is used to introduce the contrasting statement about the insufficiency of current production levels to meet future demands.