Q: In gas exchange, oxygen flows into the blood, and what flows out? Read this paragraph and choose the correct option from the provided answers: Gas exchange is the movement of oxygen into the blood and carbon dioxide out of the blood. Choices: - naturally dioxide - carbon monoxide - liquid dioxide - carbon dioxide A:
carbon dioxide

Q: What colorful arc-shaped atmospheric phenomena are produced by a combination of refraction and reflection? Read this paragraph and choose the correct option from the provided answers: Rainbows are produced by a combination of refraction and reflection. You may have noticed that you see a rainbow only when you look away from the sun. Light enters a drop of water and is reflected from the back of the drop, as shown in Figure 25.24. The light is refracted both as it enters and as it leaves the drop. Since the index of refraction of water varies with wavelength, the light is dispersed, and a rainbow is observed, as shown in Figure 25.25 (a). (There is no dispersion caused by reflection at the back surface, since the law of reflection does not depend on wavelength. ) The actual rainbow of colors seen by an observer depends on the myriad of rays being refracted and reflected toward the observer's eyes from numerous drops of water. The effect is most spectacular when the background is dark, as in stormy weather, but can also be observed in waterfalls and lawn sprinklers. The arc of a rainbow comes from the need to be looking at a specific angle relative to the direction of the sun, as illustrated in Figure 25.25 (b). (If there are two reflections of light within the water drop, another "secondary" rainbow is produced. This rare event produces an arc that lies above the primary rainbow arcsee Figure 25.25 (c). ) Rainbows Rainbows are produced by a combination of refraction and reflection. Choices: - lightning - shadows - sunsets - rainbows A:
rainbows

Q: Most of the energy used by living things comes either directly or indirectly from what? Read this paragraph and choose the correct option from the provided answers: Most of the energy used by living things comes either directly or indirectly from the sun. That's because sunlight provides the energy for photosynthesis. This is the process in which plants and certain other organisms synthesize glucose (C 6 H 12 O 6 ). The process uses carbon dioxide and water and also produces oxygen. The overall chemical equation for photosynthesis is:. Choices: - plants - the moon - the soil - the sun A:
the sun

Q: What form does formaldehyde take at room temperature? Read this paragraph and choose the correct option from the provided answers: Formaldehyde is a gas at room temperature. Acetaldehyde boils at 20C; in an open vessel, it boils away in a warm room. Most other common aldehydes are liquids at room temperature. Choices: - solid - liquids - plasma - gas A:
gas