Short answers, pulled from the story.
A cereal is a grass in the Poaceae family cultivated for its edible grain. Cereals include rice, wheat, rye, oats, barley, millet, and maize. Grains from other plant families, such as amaranth, buckwheat, and quinoa, are pseudocereals rather than true cereals.
The word cereal comes from the Latin cerealis, meaning of grain, which originally meant of the goddess Ceres. Ceres was the Roman goddess who presided over agriculture, grain crops, fertility, and motherhood.
Cereals were domesticated in the Neolithic around 8,000 years ago. Wheat and barley were domesticated in the Fertile Crescent, rice and some millets in East Asia, and sorghum and other millets in Sudan. Maize was domesticated in Mexico about 9,000 years ago.
Maize, wheat, and rice are the three largest cereals. Together they accounted for 89 percent of all cereal production worldwide in 2012 and 43 percent of the global supply of food energy in 2009.
The Green Revolution greatly increased cereal yields using mechanized tilling, monoculture, nitrogen fertilizers, and new seed strains. Between 1964 and 2023 cereal production rose by 213 percent, mostly through higher yields, while harvested area rose only 10 percent. The high-yield crops tend to have lower nutritional quality.
Cereal farming can cause soil erosion and runoff from tillage, heavy water use and aquifer salination from irrigation, and water pollution from fertilizer. It also burns large amounts of fossil fuel and can harm wildlife such as bees through pesticides. These impacts can be reduced by no-till farming, intercropping with legumes, and perennial varieties.
The Russian invasion of Ukraine in 2022 disrupted Ukrainian and Russian wheat supplies. This caused a global food price crisis in 2022 that affected countries heavily dependent on wheat flour.