Short answers, pulled from the story.
A grassland is an area or ecosystem where the vegetation is dominated by grasses, with sedges, rushes, legumes like clover, and other herbs also present. Grasslands occur naturally on all continents except Antarctica and are found in most of the Earth's ecoregions.
Grasslands cover between 31 and 69 percent of the Earth's land area, making them one of the largest biomes on the planet. Rangelands, which include grass-dominated arid and semi-arid lands, account for an estimated 70 percent of the earth's landmass.
Grasslands fall into three broad types: natural, semi-natural, and agricultural. General categories also include tropical and subtropical grasslands, temperate grasslands, flooded grasslands, montane grasslands, tundra grasslands, and desert or xeric grasslands.
Almost 90 percent of Europe's semi-natural grasslands no longer exist, a loss driven by political and economic reasons during the 20th century. Those in Western and Central Europe have almost disappeared completely, with only a few left in Northern Europe.
Grasslands hold about twenty percent of global soil carbon stocks, with carbon stored mainly in roots and soil underground. Soil carbon accounts for about 81 percent of the total ecosystem carbon in grasslands, and grasses often make up 60 to 80 percent of the biomass carbon.
According to the International Union for the Conservation of Nature, the most significant threat to grasslands is human land use, especially agriculture and mining. Global losses from grassland degradation are estimated at over $7 billion per year, with misclassification, poor protection, and cultivation adding to their vulnerability.
Semi-natural grasslands are among the most species-rich ecosystems in the world, with up to 25 plant species in 100 square centimeters. A European record on a meadow in Estonia found 76 species in one square meter, and chalk downlands in England can support over 40 species per square meter.