In 1628, English physician William Harvey established that the blood circulates throughout the body. He recognized that the heart acts as a pump and does not work by using up blood as earlier anatomists thought. To carefully observe the beating of the heart and the direction of blood flow, Harvey needed to see the works of the blood in slow motion. Since there was no way for him to observe a human heart in slow motion, he studied the hearts of toads and snakes, rather than the rapidly beating hearts of "warm-blooded" mammals and birds. By keeping these animals cool, he could slow their hearts down. The main argument for his conclusion that the blood circulates stemmed from his measurement of the amount of blood pumped with each heartbeat. He calculated that the amount of blood pumped each hour by far exceeds the total amount of blood in the body and proved that the same blood passes through the heart over and over again.What misconception did scientist harbor before Harveys study?
In 1628, English physician William Harvey established that the blood circulates throughout the body. He recognized that the heart acts as a pump and does not work by using up blood as earlier anatomists thought. To carefully observe the beating of the heart and the direction of blood flow, Harvey needed to see the works of the blood in slow motion. Since there was no way for him to observe a human heart in slow motion, he studied the hearts of toads and snakes, rather than the rapidly beating hearts of "warm-blooded" mammals and birds. By keeping these animals cool, he could slow their hearts down. The main argument for his conclusion that the blood circulates stemmed from his measurement of the amount of blood pumped with each heartbeat. He calculated that the amount of blood pumped each hour by far exceeds the total amount of blood in the body and proved that the same blood passes through the heart over and over again.Which of the following did Harvey do?I. Observe the heartbeat and blood flow in snakes and frogs.II. Determine that the heart acts as a pump.III. Count the number of blood cells that pass through the heart every hour.IV. Show that the blood circulates.
Radiation from radioisotopes can be used to kill cancer cells. Chemist Marie Curie received two Nobel Prizes for her work with radioisotopes. Her work led to the discovery of the neutron and synthesis of artificial radioactive elements. She died of leukemia at 67, caused by extensive exposure to radiation. Curie never believed that radium and other materials she worked with were a health hazard. In World War I, glowing radium was used on watch dials to help soldiers read their watches in the dark and to synchronize their attacks. Unfortunately, women who worked in factories were drawing their radium stained brushes to fine points by putting them between their lips. As a result, their teeth would glow in the dark. But this was an amusement for children more than a cause of worry. About ten years later, the women developed cancer in their jaws and mouths and had problems making blood cells. This exposed the dangers of radiation.Based on the information in the passage, which statement about radioisotopes is false?
Radiation from radioisotopes can be used to kill cancer cells. Chemist Marie Curie received two Nobel Prizes for her work with radioisotopes. Her work led to the discovery of the neutron and synthesis of artificial radioactive elements. She died of leukemia at 67, caused by extensive exposure to radiation. Curie never believed that radium and other materials she worked with were a health hazard. In World War I, glowing radium was used on watch dials to help soldiers read their watches in the dark and to synchronize their attacks. Unfortunately, women who worked in factories were drawing their radium stained brushes to fine points by putting them between their lips. As a result, their teeth would glow in the dark. But this was an amusement for children more than a cause of worry. About ten years later, the women developed cancer in their jaws and mouths and had problems making blood cells. This exposed the dangers of radiation.Which dangers of radiation were mentioned in the passage?I. Radiation can cause genetic mutations.II. Radiation can lead to leukemia.III. Radiation can cause chemotherapy.
In the past, people thought that the Earth was flat and that a ship that sailed too far would fall off the edge of the world. The Earth appears flat because the Earth is too large for humans on Earth to see its curvature. Several events helped shed the misconceptions. For one, during a lunar eclipse, the Earth is positioned between the sun and the moon. It eclipses the moon by casting a shadow on it. The shadow the Earth casts is round. When Magellan circumnavigated the Earth, he proved that one could not fall off the edge of the Earth, because the Earth was round and had no edges. Finally, space missions provided us with images of our round Earth from far away and showed us how beautiful our planet looks, even from a distance.In the passage, what was cited as proof that the Earth is round? a. Earth casts a round shadow on the moon during a lunar eclipse. b. Earth revolves around the sun. c. Magellan circumnavigated the Earth. d. images from space
In the past, people thought that the Earth was flat and that a ship that sailed too far would fall off the edge of the world. The Earth appears flat because the Earth is too large for humans on Earth to see its curvature. Several events helped shed the misconceptions. For one, during a lunar eclipse, the Earth is positioned between the sun and the moon. It eclipses the moon by casting a shadow on it. The shadow the Earth casts is round. When Magellan circumnavigated the Earth, he proved that one could not fall off the edge of the Earth, because the Earth was round and had no edges. Finally, space missions provided us with images of our round Earth from far away and showed us how beautiful our planet looks, even from a distance.With which misconception about the Earth is the passage concerned?
