The common name is valve cover, so the correct answer is A.
Terrorist attacks on the United States is the answer.
On September 11, 2001 that was the day New York got attacked by terrorists. The Twin Towers were the ones that got affected, 2,996 people (maybe more) died during that attacked. The terrorists were one of the 2,996 people that died (19 of them died). more than 6,000 were injured that day.
#NeverForget
Hope this helped
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The change in pitch of a train's horn as it passes while you are
standing still can be described by the Doppler effect, but that
doesn't explain it.
Answer:
gravitational waves are ripples in spece-time caused primarily when objects are accelerated and the energy for the acceleration is transpoted as gravitational radiation.
they are difficult to detect because they require very sensitive technology or you will have to wait unitl black holes collide.
