Which of the following grains is considered chometz during Passover?

During Passover, chometz refers specifically to leavened products made from certain grains that can ferment and rise. The grains that are considered chometz are wheat, barley, oats, spelt, and rye. As such, wheat is included in this category because it can be used to make items that would leaven or rise when mixed with water. This is why wheat is viewed as chometz during the Passover holiday.

The other grains listed, such as rice, corn, and millet, do not fall under the category of chometz because they do not create leavened products in the same way that wheat and the other specified grains do. Thus, they are generally allowed for consumption during Passover by those who practice observance of this dietary restriction.