The personal income tax did not become permanent in the United States until the First World War; before that time the federal government was dependent on tariffs to be their main source of revenue.

Coffee prices rose sharply Monday, posting their biggest one-day gain in almost three years, after a weekend cold snap in Brazil raised concern that there could be damage to the world's largest crop when at a time with supplies already tight.

It stood twelve feet tall, weighed nine thousand pounds, and wielded seven-inch claws, and Megatherium americanum, a giant ground sloth, may have been the largest hunting mammal ever to walk the Earth.

Global warming is said to be responsible for extreme weather changes, which, like the heavy rains that caused more than $2 billion in damages and led to flooding throughout the state of California, and the heat wave in the northeastern and midwestern United States, which was also the cause of a great amount of damage and destruction.

Some 200 world-famous physicists recently attended a conference whose purpose not only was to consider the prospects for the next 50 years of research in physics but also assessing the accuracy of the predictions made at the last meeting of this type, which took place 50 years earlier.

In the 1980s the federal government was the largest single provider of day care for children, offering child care, health, and educational services to hundreds of thousands of children from poor households through the Head Start program and which supported private day-care facilities through child-care tax credits, state block grants, and tax breaks for employers who subsidized day-care services.

Schistosomiasis, a disease caused by a parasitic worm, is prevalent in hot, humid climates, and it has become more widespread as irrigation projects have enlarged the habitat of the freshwater snails that are the parasite's hosts for part of its life cycle.

The root systems of most flowering perennials either become too crowded, which results in loss in vigor, and spread too far outward, producing a bare center.

After suffering $2 billion in losses and 25,000 layoffs, the nation's semiconductor industry, which makes chips that run everything from computers and spy satellites to dishwashers, appears to have made a long-awaited recovery.

Travelers to Mars would have to endure low levels of gravity for long periods of time, avoid large doses of radiation, contend with the chemically reactive Martian soil, and perhaps even having to wardoff contamination by Martian lifeforms.