Why was the US detonation of a hydrogen bomb in 1952 and the Soviet detonation of one in 1953 significant?
It signaled that the Soviet Union was spying on the United States.
It was a sign that the United States was better at producing dangerous weapons.
It was a sign that the countries would soon threaten each other with war.
It signaled that the arms race was producing stronger, more dangerous weapons.

The Battle of Concord in 1775 was very costly for both sides. For the Colonist 43 men were lost, and 73 men were lost in the British side. Even though the Colonist lost many Minutemen, it was viewed as a significant military victory for them.

The correct answer is B, because the Colonist showed the British troops that they were prepared for the conflict. Furthermore, the Colonist sent a message to King George III and the British in general, that such actions will not be accepted  and they were ready to fight the British troops at any cost.

Many historians also agree that the battle of Concord and the Battle of Lexington in the same year, were the preliminary military conflicts that started the American Revolution.