Unrestricted submarine warfare, which became prominent in World War I, meant that submarines could sink any time of vessel at any time without warning. Before this, they had to surface first and place crews on lifeboats.
Answer:~At the center, information about tides and currents was collected, more accurate charts and maps were drawn, techniques for determining longitude were improved, and new ship designs (such as the caravel) were developed
Answer:
a - the treaty that ended the us Mexican war
Explanation:
The Treaty of Guadalupe Hidalgo, signed on February 2, 1848, ended the Mexican-American War in favor of the United States. Mexico also gave up all claims to Texas and recognized the Rio Grande as America's southern boundary
Answer: d.
Explanation: they used them to spy on each other
The booming economy led in 1929 to a backlog of business inventories which was three times larger than the year before. As a result a recession began in August 1929, two months before the stock market crash. During this two month period, production declined at an annual rate of
20 percent. This decline resulted in the stock market crash which began October 24, followed by Black Tuesday on October 29. Losses for the month amounted to $16 billion, an astronomical sum in those days.
1932 and 1933 were the worst years of the Great Depression. Industrial stocks lost 80 percent of their value since 1930. 10,000 banks failed , or 40 percent of the 1929 total. GNP fell 31 percent since 1929 and over 13 million Americans lost their jobs between 1929 and 1932. In 1933 unemployment did rise to 24.9 percent.
The desperation of many people and especially veterans from WW I resulted in spectacular events, the most dramatic the so-called Bonus marches in 1932.