Answer the following question given this paragraph: The disintegration of unstable nuclei does not occur all at once. The rate of disintegration is a statistical process. The most convenient way to consider it is by a concept known as half-life . The time required for half of the atoms in any given quantity of a radioactive substance to decay is the half-life of that element. Each particular isotope has its own half-life. For example, the half-life of radium-226 is 1600 years. That is, beginning with 1.00 gram of radium-226, it would take 1600 years for half of it to decay and leave 0.50 gram remaining. After another 1600 years, only 0.25 gram would remain. In each half-life, exactly half of the beginning amount decays. Q: What is the time it takes for radioactive substance to decay? Choices: - decay rate - full-life - deterioration rate - half-life A:
half-life
Answer the following question given this paragraph: Longshore drift continually moves sand along the shore. Deposition occurs where the water motion slows. The smallest particles, such as silt and clay, are deposited away from shore. This is where the water is calmer. Larger particles are deposited onshore. This is where waves and other motions are strongest. Q: What occurs where the water motion slows? Choices: - diffusion - vapor - erosion - deposition A:
deposition
Q: Answer the following question given this paragraph: 17.4 Doppler Effect and Sonic Booms The characteristic sound of a motorcycle buzzing by is an example of the Doppler effect. The high-pitch scream shifts dramatically to a lower-pitch roar as the motorcycle passes by a stationary observer. The closer the motorcycle brushes by, the more abrupt the shift. The faster the motorcycle moves, the greater the shift. We also hear this characteristic shift in frequency for passing race cars, airplanes, and trains. It is so familiar that it is used to imply motion and children often mimic it in play. The Doppler effect is an alteration in the observed frequency of a sound due to motion of either the source or the observer. Although less familiar, this effect is easily noticed for a stationary source and moving observer. For example, if you ride a train past a stationary warning bell, you will hear the bell's frequency shift from high to low as you pass by. The actual change in frequency due to relative motion of source and observer is called a Doppler shift. The Doppler effect and Doppler shift are named for the Austrian physicist and mathematician Christian Johann Doppler (18031853), who did experiments with both moving sources and moving observers. Doppler, for example, had musicians play on a moving open train car and also play standing next to the train tracks as a train passed by. Their music was observed both on and off the train, and changes in frequency were measured. What causes the Doppler shift? Figure 17.14, Figure 17.15, and Figure 17.16 compare sound waves emitted by stationary and moving sources in a stationary air mass. Each disturbance spreads out spherically from the point where the sound was emitted. If the source is stationary, then all of the spheres representing the air compressions in the sound wave centered on the same. Q: The characteristic sound of a motorcycle buzzing by is an example of which effect? Choices: - warp effect - coreolis effect - polar effect - doppler effect A:
A: doppler effect
Question: Answer the following question given this paragraph: To research how characteristics are passed from parents to offspring, Mendel needed to control pollination. Pollination is the fertilization step in the sexual reproduction of plants. Pollen consists of tiny grains that are the male gametes of plants. They are produced by a male flower part called the anther (see Figure below ). Pollination occurs when pollen is transferred from the anther to the stigma of the same or another flower. The stigma is a female part of a flower. It passes the pollen grains to female gametes in the ovary. Q: What is the fertilization step in the sexual reproduction of plants? Choices: - hibernation - Fornications - evolution - pollination A:
Answer: pollination
*Question*
Answer the following question given this paragraph: distinctly differ from the adult form, spending 3 to 15 years as suspension feeders. Once they attain sexual maturity, the adults reproduce and die within days. Lampreys possess a notochord as adults; however, this notochord is surrounded by a cartilaginous structure called an arcualia, which may resemble an evolutionarily early form of the vertebral column. Q: What do we call the cartilaginous structure that surrounds the notochrod? Choices: - osteocytes - clavicle - membrane - arcualia A:
**Answer**
arcualia
Q: Answer the following question given this paragraph: Secondary pollutants are formed when primary pollutants interact with sunlight, air, or each other. They do not directly cause pollution. However, when they interact with other parts of the air, they do cause pollution. For example, ozone is created when some pollutants interact with sunlight. High levels of ozone in the atmosphere can cause problems for humans. Q: What are formed when primary pollutants interact with sunlight, air, or each other? Choices: - cross pollutants - typical pollutants - secondary contaminants - secondary pollutants A:
A: secondary pollutants