This is an excerpt from a letter written by a soldier fighting in World War I and sent to his mother
The trenches stretch for miles, but even though they are
almost 12 feet deep we can't walk around much. The
bullets and grenades rain down upon us at even the
slightest hint of movement, so all we can do is lean in
stillness, waiting, trying not to make a sound
Which statement est represents the main idea of this source)
A Trenches were used extensively in World War
B. The soldier's mother is worried about her son
Tenches are often dug almost 12 feet deep
Fighting in a World War I trench was boring and dangerous NO FILES

I think the answer should be: Fighting in a World War I trench wad boring and dangerous

C. Fighting in a World War I trench was boring and dangerous.

Explanation:

The soldier talks about how dangerous it was because of the grenades and bullets raining down on them. He also mentions how you cannot move and have to sit still waiting.

answer; people where able to travel across the u.s.a faster than any other mode of transportation,travel time was about a week,from coast to coast

answer:   migrations were important in the neolithic period. "two major migrations passing through southeastern europe were confirmed by the means of archaeo-genetic studies."

the first migration was the early neolithic period -- 6,000 before common era (bce) -- when the first farmers, from anatolia -- asia minor -- spread through europe. the second migration occurred during the early bronze age (3,000-2,500 bce) when the so-called "steppe population," from the eurasian steppe, replaced much of northern europe's previous population.

the first farmers of northern and western europe passed through southeastern europe with limited hunter-gatherer genetic admixture, which occurs when two or more previously isolated populations begin interbreeding. however, some groups that remained mixed extensively -- without the male-biased, hunter-gatherer admixture that prevailed later in the north and west, according to latest discoveries. southeastern europe continued to be a nexus between east and west, with intermittent genetic contact with the steppe people up to 2,000 years before the migrations that replaced much of northern europe's population.

"in some places, hunter-gatherers and incoming farmers seem to have mixed very quickly," says iain mathieson, a geneticist at the university of pennsylvania, who was first author of the paper. "but, mostly, the two groups remained isolated, at least for the first few hundred years. these hunter-gatherers had been living there for thousands of years, and it must have been quite a shock to have these new people show up -- with a completely different lifestyle and appearance."