Answer the following question given this paragraph: 23.6 Back Emf It has been noted that motors and generators are very similar. Generators convert mechanical energy into electrical energy, whereas motors convert electrical energy into mechanical energy. Furthermore, motors and generators have the same construction. When the coil of a motor is turned, magnetic flux changes, and an emf (consistent with Faraday's law of induction) is induced. The motor thus acts as a generator whenever its coil rotates. This will happen whether the shaft is turned by an external input, like a belt drive, or by the action of the motor itself. That is, when a motor is doing work and its shaft is turning, an emf is generated. Lenz's law tells us the emf opposes any change, so that the input emf that powers the motor will be opposed by the motor's self-generated emf, called the back emf of the motor. (See Figure 23.25. Q: The motor thus acts as a generator whenever its coil does what? Choices: - stops - revolves - oscillates - rotates A:
rotates
Answer the following question given this paragraph: 25.9 Regulation of Fluid Volume and Composition The major hormones regulating body fluids are ADH, aldosterone and ANH. Progesterone is similar in structure to aldosterone and can bind to and weakly stimulate aldosterone receptors, providing a similar but diminished response. Blood pressure is a reflection of blood volume and is monitored by baroreceptors in the aortic arch and carotid sinuses. When blood pressure increases, more action potentials are sent to the central nervous system, resulting in greater vasodilation, greater GFR, and more water lost in the urine. ANH is released by the cardiomyocytes when blood pressure increases, causing Na+ and water loss. ADH at high levels causes vasoconstriction in addition to its action on the collecting ducts to recover more water. Diuretics increase urine volume. Mechanisms for controlling Na+ concentration in the blood include the reninangiotensinaldosterone system and ADH. When Na+ is retained, K+ is excreted; when Na+ is lost, K+ is retained. When circulating Ca++ decreases, PTH stimulates the reabsorption of Ca++ and inhibits reabsorption of HPO 24 . pH is regulated through buffers, expiration of CO2, and excretion of acid or base by the kidneys. The breakdown of amino acids produces ammonia. Most ammonia is converted into less-toxic urea in the liver and excreted in the urine. Regulation of drugs is by glomerular filtration, tubular secretion, and tubular reabsorption. Q: Baroreceptors in the aortic arch and carotid sinuses monitor what level in the body? Choices: - hunger - air intake - temperature - blood pressure A:
blood pressure
Q: Answer the following question given this paragraph: The dense, iron core forms the center of the Earth. Scientists know that the core is metal from studying metallic meteorites and the Earth's density. Seismic waves show that the outer core is liquid, while the inner core is solid. Movement within Earth's outer liquid iron core creates Earth's magnetic field. These convection currents form in the outer core because the base of the outer core is heated by the even hotter inner core. Q: Seismic waves show that the inner core of the earth is solid while the outer core is what? Choices: - gas - lava - silicon - liquid A:
A: liquid
Question: Answer the following question given this paragraph: Elevation measures how high land is above sea level. It gets colder as you go higher above sea level, which is why you see snow-capped mountains. Q: What term is used to express the measurement of how high land is above sea level? Choices: - knots - latitude - distance - elevation A:
Answer: elevation
*Question*
Answer the following question given this paragraph: The skin helps maintain a constant body temperature. It keeps the body cool in two ways. Sweat from sweat glands in the skin evaporates to cool the body. Blood vessels in the skin dilate, or widen, increasing blood flow to the body surface. This allows more heat to reach the surface and radiate into the environment. The opposite happens to retain body heat. Blood vessels in the skin constrict, or narrow, decreasing blood flow to the body surface. This reduces the amount of heat that reaches the surface so less heat is lost to the environment. Q: What in the skin dilates, or widens, in order to increase blood flow to the bodys surface? Choices: - veins - pores - tear ducts - blood vessels A:
**Answer**
blood vessels
Q: Answer the following question given this paragraph: Another major step in animal evolution was the evolution of a notochord. A notochord is a rigid rod that runs the length of the body. It supports the body and gives it shape (see Figure below ). It also provides a place for muscles to anchor, and counterbalances them when they contract. Animals with a notochord are called chordates. They also have a hollow nerve cord that runs along the top of the body. Gill slits and a tail are two other chordate features. Many modern chordates have some of these structures only as embryos. Q: A major step in animal evolution was the evolution of what rigid rod that runs the length of the body? Choices: - limbic system - endoderm - mitochondria - notochord A:
A: notochord