Answer the following question given this paragraph: During World War II, battleships and submarines carried echo sounders. Their goal was to locate enemy submarines ( Figure below ). Echo sounders produce sound waves that travel outward in all directions. The sound waves bounce off the nearest object and then return to the ship. Scientists know the speed of sound in seawater. They then can calculate the distance to the object that the sound wave hit. Most of these sound waves did not hit submarines. They instead were used to map the ocean floor. Q: What produces sound waves that travel outward in all directions in water? Choices: - echo chamber - ultrasound machines - amplifiers - echo sounders A:
echo sounders
(Question)
Answer the following question given this paragraph: Water is the only substance on Earth that is stable in all three states. Q: What is the only substance on earth that is stable in all three states? Choices: - carbon - mercury - air - water A:
(Answer)
water
Ques: Answer the following question given this paragraph: The development of modern lasers has opened many doors to both research and applications. A laser beam was used to measure the distance from the Earth to the moon. Lasers are important components of CD players. As the image above illustrates, lasers can provide precise focusing of beams to selectively destroy cancer cells in patients. The ability of a laser to focus precisely is due to high-quality crystals that help give rise to the laser beam. A variety of techniques are used to manufacture pure crystals for use in lasers. Q: What was used to measure the distance between the earth and the moon? Choices: - telescope - yardstick - ultrasound - laser beam A:
Ans: laser beam
(Q).
Answer the following question given this paragraph: The Figure below shows the direction of the current that is generated by a moving magnet. If the magnet is moved back and forth repeatedly, the current keeps changing direction. In other words, alternating current (AC) is produced. Alternating current is electric current that keeps reversing direction. Q: What is the term for electric current that keeps reversing direction? Choices: - direct current - AC/DC - magnetic current - alternating current A:
(A).
alternating current
Ques:Answer the following question given this paragraph: The right ventricle pumps oxygen-poor blood toward the lungs, where it receives oxygen. Q: The right ventricle pumps what type of blood toward the lungs? Choices: - plasma - oxygenated - oxygen-rich - oxygen-poor A:

Ans:oxygen-poor
Question: Answer the following question given this paragraph: Respiration is the process in which gases are exchanged between the body and the outside air. Q: What is the main organ required for respiration in mammals? Choices: - the diaphragm - the heart - the brain - the lungs A:
Answer:
the lungs