Answer:
The USA became involved in Vietnam because it feared the spread of communism. The USA were unable to defeat the Vietcong and were met with growing opposition to the war back home.
this is the only one I can answer, I'm sorry. I hope this helps though
<span>Seismic waves are the waves of energy caused by the sudden breaking of rock within the earth or an explosion. They are the energy that travels through the earth and is recorded on seismographs.
Source: OS</span>
Answer:
Radioactive isotopes are unstable and will decay. ... The isotopes will decay into a stable isotope over time. Scientists can tell how old the rock was from looking at the radioactive isotope's half-life, which tells them how long it would take for there to be half the radioactive isotope and half the stable isotope.
Thomas Alva Edison<span> (February 11, 1847 – October 18, 1931) was an American inventor and businessman, who has been described as America’s greatest inventor.</span><span> He developed many devices that greatly influenced life around the world, including the </span>phonograph<span>, the </span>motion picture camera<span>, and the long-lasting, practical electric </span>light bulb<span>. </span><span>the most important thing to be successful is his famous quote:
</span><span>Genius is one percent inspiration and ninety-nine percent perspiration.</span>
