Answer the following question given this paragraph: Unlike bones and tendons, which need to be strong as well as elastic, the arteries and lungs need to be very stretchable. The elastic properties of the arteries are essential for blood flow. The pressure in the arteries increases and arterial walls stretch when the blood is pumped out of the heart. When the aortic valve shuts, the pressure in the arteries drops and the arterial walls relax to maintain the blood flow. When you feel your pulse, you are feeling exactly thisthe elastic behavior of the arteries as the blood gushes through with each pump of the heart. If the arteries were rigid, you would not feel a pulse. The heart is also an organ with special elastic properties. The lungs expand with muscular effort when we breathe in but relax freely and elastically when we breathe out. Our skins are particularly elastic, especially for the young. A young person can go from 100 kg to 60 kg with no visible sag in their skins. The elasticity of all organs reduces with age. Gradual physiological aging through reduction in elasticity starts in the early 20s. Q: What causes reduction of elasticity in all organs? Choices: - low vitamin D - radiation - weight gain - age A:
age

Answer the following question given this paragraph: For a given substance, the entropy of the liquid state is greater than the entropy of the solid state. Likewise, the entropy of the gas is greater than the entropy of the liquid. Therefore, entropy increases in processes in which solid or liquid reactants form gaseous products. Entropy also increases when solid reactants form liquid products. Q: What increases in processes in which solid or liquid reactants form gaseous products and when solid reactants form liquid products? Choices: - evaporation - glucose - respiration - entropy A:
entropy

Answer the following question given this paragraph: Discussion The intensity goes up by a factor of 4 when the amplitude doubles. This answer is a little disquieting. The two individual waves each have intensities of 1.00 W/m 2 , yet their sum has an intensity of 4.00 W/m 2 , which may appear to violate conservation of energy. This violation, of course, cannot happen. What does happen is intriguing. The area over which the intensity is 4.00 W/m 2 is much less than the area covered by the two waves before they interfered. There are other areas where the intensity is zero. The addition of waves is not as simple as our first look in Superposition and Interference suggested. We actually get a pattern of both constructive interference and destructive interference whenever two waves are added. For example, if we have two stereo speakers putting out 1.00 W/m 2 each, there will be places in the room where the intensity is 4.00 W/m 2 , other places where the intensity is zero, and others in between. Figure 16.45 shows what this interference might look like. We will pursue interference patterns elsewhere in this text. Q: Two types of interference found in waves are constructive and what else? Choices: - osmotic - conductive - primitive - destructive A:
destructive