Ichthyosaurs had a higher chance of being preserved than did terrestrial creatures because, as marine animals, they tended to live in environments less subject to erosion.


The quality of preservation is outstanding, but what is even more impressive is the number of ichthyosaur fossils containing preserved embryos.


After toiling up the Missouri all summer, the group wintered near the Mandan villages in the center of what is now North Dakata.


Lewis and Clark brought back much new information, including the knowledge that the continent was wider than originally supposed


Using only stone and wood tools, and without benefit of wheels or draft animals, the builders quarried ton upon ton of sandstone from the canyon walls, cut it into small blocks, hauled the blocks to the construction site, and fitted them together with mud mortar.

The rocks of the crust are of very different ages. Some continental rocks are over 3,000 million years old, while those of the ocean floor are less than 200 million yeas old.


Given that two-thirds of the Earth’s surface is water and that marine lives at all levels of the ocean, the total three-dimensional living space of the ocean is perhaps 100 times greater than that of land and contains more than 90 percent of all life on Earth even though the ocean has fewer distinct species.


Science involves imagination and creative thinking as well as collecting information and performing experiments.


Science is built with facts just as a house I built with bricks, but a collection of facts cannot be called science any other than a pile of bricks can be called a house.

In the early nineteenth century, the knowledge of the physics of heat, which was essential to a science of refrigeration was rudimentary.

Rapid industrialization and increased geographic mobility in the nineteenth century had special implications for women because these changes tended to magnify social distinctions.


Anthropology is a science in that anthropologists use a rigorous set of methods and techniques to document observations that can be checked by others.


With the growing prosperity brought on by the second world war and the economic boom that followed it , young people married and established households earlier and began to raise larger families than did their predecessors during the Depression.

These researchers have sought to demonstrate that their work can be a valuable tool not only of science but also of history, providing fresh insights into the daily lives of ordinary people whose existences might not otherwise be so well documented.


Technical difficulties aside, crow research is daunting because the ways of these birds are so complex and various.

It was not until after the Second World War that physicists began trying to make stimulated emission dominate.

Deeper still, the pressure is even more intense, preventing the rock from melting in spite of a higher temperature.

The range of the New York canal system was still further extended when the states of Ohio and Indiana, inspired by the success of the Eric Canal, provided water conncetions between Lake Eric and the Ohio River.

It is commonly believed that in the United States that school is where people to get an education. Nevertheless, it has been said that today children interrupt their education to to school. The distinction between schooling and education implied by this remark line is important.

The states encouraged internal improvements in two distinct ways: first, by actually establishing state companies to build such improvements; second, by providing part of the capital for mix public-private companies setting out to make a profit.


Per capita income is a nations entire income divided by the number of people in the nation.


Desert animals can drink prodigious volumes in a short time and camel have been kown to imbibe over 100 liters in a few minutes. A very dehydrated person, on the other hand, cannot drink enough water to hydrate at on session, because the human stomach is not sufficiently big and because a too rapid dilution of the body fluids causes death from water intoxication.
While still growing, crops belonged to the men who, in contrast to most other Native American groups, planted.


Barbed wire, first patented in the United States in 1867, played an important part in the development of American farming, as it enabled the setters to make effective fencing to enclose their land and keep cattle away from their crops.

The pressure exerted on the human body increases by 1 atmosphere for every 10 meters of depth in se