The y-axis on a graph provides information about the vertical measure being represented. In the context of the options given, the y-axis typically represents one of these variables:
How much grain was produced : If the y-axis is labeled with quantities such as kilograms, tons, or any other unit of measurement for grain, it indicates the amount of grain produced.
How many workers produced the grain : If the y-axis is labeled with numbers representing people, it shows the number of workers involved in production.
The period of time this information was gathered : Time is usually displayed on the x-axis, as it is common to show how a certain value changes over time. However, there might be specific circumstances where time could be shown on the y-axis, especially in vertical timelines or certain types of plots.
The countries where this information was gathered : Generally, the countries or other categories are placed along the x-axis, while the y-axis might display a quantity associated with each category.
Based on general graphing practices, the option that most logically represents information on the y-axis is:
How much grain was produced
This option aligns with typical uses of the y-axis, which is often used to show the magnitude or quantity of a certain variable.