Thomas Malthus published his Essay on the Principle of Population almost 200 years ago. Ever since then, forecasters have being warning 【M1】 ______ that worldwide famine was just around the next comer. The fast-growing population's demand for food, they warned, would soon exceed their 【M2】 ______ supply, leading to widespread food shortages and starvation. But in reality, the world's total grain harvest has risen steadily over the years. Except for relative isolated trouble spots like present-day Somalia, 【M3】 ______ and occasional years of good harvests, the world's food crisis has remained 【M4】 ______ just around the comer. Most experts believe this can continue even as ff 【M5】 ______ the population doubles by the mid-21st century, although feeding l0 billion people will not be easy for politics, economic and environmental reasons. 【M6】 ______ Optimists point to concrete examples of continued improvements in yield. In Africa, by instance, improved seeds, more fertilizers and advanced 【M7】 ______ growing practices have more than double com and wheat yields in an 【M8】 ______ experiment. Elsewhere, rice experts in the Philippines are producing a plant with few stems and more seeds. There is no guarantee that plant 【M9】 ______ breeders can continue to develop new, higher-yielding crop, but most 【M10】______ researchers see their success to date as reason for hope. 【M1】