Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Q: Context: From the outside, the skin looks plain and simple, as you can see in Figure 16.5. But at a cellular level, theres nothing plain or simple about it. A single square inch of skin contains about 20 blood vessels, hundreds of sweat glands, and more than a thousand nerve endings. It also contains tens of thousands of pigment-producing cells. Clearly, there is much more to skin than meets the eye! For a dramatic introduction to the skin, watch this video: MEDIA Click image to the left or use the URL below. URL: The skin is only about 2 mm thick, or about as thick as the cover of a book. Although it is very thin, it consists of two distinct layers, called the epidermis and the dermis. You can see both layers and some of their structures in Figure 16.6. Refer to the figure as you read about the epidermis and dermis below. The epidermis is the outer layer of skin. It consists almost entirely of epithelial cells. There are no blood vessels, nerve endings, or glands in this skin layer. Nonetheless, this layer of skin is very active. It is constantly being renewed. How does this happen? 1. The cells at the bottom of the epidermis are always dividing by mitosis to form new cells. 2. The new cells gradually move up through the epidermis toward the surface of the body. As they move, they produce the tough, fibrous protein called keratin. 3. By the time the cells reach the surface, they have filled with keratin and died. On the surface, the dead cells form a protective, waterproof layer. 4. Dead cells are gradually shed from the surface of the epidermis. As they are shed, they are replaced by other dead cells that move up from below. The epidermis also contains cells called melanocytes. You can see a melanocyte in Figure 16.7. Melanocytes produce melanin. Melanin is a brown pigment that gives skin much of its color. Everyones skin has about the same number of melanocytes per square inch. However, the melanocytes of people with darker skin produce more melanin. The amount of melanin that is produced depends partly on your genes and partly on how much ultraviolet light strikes your skin. The more light you get, the more melanin your melanocytes produce. This explains why skin tans when its exposed to sunlight. The dermis is the inner layer of skin. It is made of tough connective tissue. The dermis is attached to the epidermis by fibers made of the protein collagen. The dermis is where most skin structures are located. Look again at Figure pain, pressure, and temperature. If you cut your skin and it bleeds, the cut has penetrated the dermis and damaged a blood vessel. The cut probably hurts as well because of the nerve endings in this skin layer. The dermis also contains hair follicles and two types of glands. You can see some of these structures in Figure 16.8. Hair follicles are structures where hairs originate. Each hair grows out of a follicle, passes up through the epidermis, and extends above the skin surface. Sebaceous glands are commonly called oil glands. They produce an oily substance called sebum. Sebum is secreted into hair follicles. Then it makes its way along the hair shaft to the surface of the skin. Sebum waterproofs the hair and skin and helps prevent them from drying out. Sweat glands produce the salty fluid known as sweat. Sweat contains excess water, salts, and other waste products. Each sweat gland has a duct that passes through the epidermis. Sweat travels from the gland through the duct and out through a pore on the surface of the skin. You couldnt survive without your skin. It has many important functions. In several ways, it helps maintain homeostasis. The main function of the skin is controlling what enters and leaves the body. It prevents the loss of too much water from the body. It also prevents bacteria and other microorganisms from entering the body. Melanin in the epidermis absorbs ultraviolet light. This prevents the light from reaching and damaging the dermis. The skin helps maintain a constant body temperature. It 
 Question: __oily substance secreted by glands in the skin

A: sebum
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Q: Context: After a win at Cleveland, the Steelers traveled to Baltimore to take on the Ravens in what would be the Thanksgiving Primetime Game and of course their first game on Thanksgiving Day since 1998. The Ravens drew first blood as Joe Flacco found Torrey Smith on a 7-yard pass to make the score 7-0 in the first quarter. In then 2nd quarter, Justin Tucker nailed a 43-yard field goal for a 10-0 halftime lead. After the break, the Ravens went back to work in the 3rd quarter as Tucker nailed a 34-yard field goal for a 13-0 lead. The Steelers finally got on the board asBen Roethlisberger found Emmanuel Sanders on an 8-yard touchdown pass for a 13-7 score. The Ravens then pulled away as Tucker kicked yet another field goal putting his team ahead by 9, 16-7. In the 4th quarter, Tucker kicked yet another field goal this one from 45 yards out for a score of 19-7. The Steelers managed to draw within 5 points 19-14 when Le'Veon Bell ran for a 1-yard touchdown. Tucker then kicked a 48-yard field goal to make the score 22-14. The Steelers started their comeback attempt as Roethlisberger found Jerricho Cotchery on a 1-yard touchdown pass for a 22-20 score. After this, they tried the 2-point conversion to tie the game and send it into OT, but they would come up short and miss the conversion with 1:03 left in the game. This dropped the team to 5-7 and 3rd place in the AFC North. Also they dropped to 2-5 on Thanksgiving. 
 Question: Which team went scoreless in the first quarter?

A: steelers
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Q: Context: A solenoid is a coil of wire with electric current flowing through it, giving it a magnetic field (see Figure 25.5). Recall that current flowing through a straight wire produces a weak electromagnetic field that circles around the wire. Current flowing through a coil of wire, in contrast, produces a magnetic field that has north and south poles like a bar magnet. The magnetic field around a coiled wire is also stronger than the magnetic field around a straight wire because each turn of the wire has its own magnetic field. Adding more turns increases the strength of the field, as does increasing the amount of current flowing through the coil. You can see an actual solenoid with a compass showing its magnetic north pole at this URL: . Solenoids are the basis of electromagnets. An electromagnet is a solenoid wrapped around a bar of iron or other ferromagnetic material (see Figure 25.6). The electromagnetic field of the solenoid magnetizes the iron bar by aligning its magnetic domains. The combined magnetic force of the magnetized iron bar and the wire coil makes an electromagnet very strong. In fact, electromagnets are the strongest magnets made. Some of them are strong enough to lift a train. The maglev train described earlier, in the lesson "Electricity and Magnetism," contains permanent magnets. Strong electromagnets in the track repel the train magnets, causing the train to levitate above the track. Like a solenoid, an electromagnet is stronger if there are more turns in the coil or more current is flowing through it. A bigger bar or one made of material that is easier to magnetize also increases an electromagnets strength. You can see how to make a simple electromagnet at this URL: (4:57). MEDIA Click image to the left or use the URL below. URL: Many common electric devices contain electromagnets. Some examples include hair dryers, fans, CD players, telephones, and doorbells. Most electric devices that have moving parts contain electric motors. You can read below how doorbells and electric motors use electromagnets. Figure 25.7 shows a diagram of a simple doorbell. Like most doorbells, it has a button located by the front door. Pressing the button causes two electric contacts to come together and complete an electric circuit. In other words, the button is a switch. The circuit is also connected to a voltage source, an electromagnet, and the clapper of a bell. When current flows through the circuit, the electromagnet turns on, and its magnetic field attracts the clapper. This causes the clapper to hit the bell, making it ring. Because the clapper is part of the circuit, when it moves to strike the bell, it breaks the circuit. Without current flowing through the circuit, the electromagnet turns off. The clapper returns to its original position, which closes the circuit again and turns the electromagnet back on. The electromagnet again attracts the clapper, which hits the bell once more. This sequence of events keeps repeating as long as the button by the front door is being pressed. An electric motor is a device that uses an electromagnet to change electrical energy to kinetic energy. Figure 25.8 shows a simple diagram of an electric motor. The motor contains an electromagnet that is connected to a shaft. When current flows through the motor, the electromagnet turns, causing the shaft to turn as well. The rotating shaft moves other parts of the device. Why does the motors electromagnet turn? Notice that the electromagnet is located between the north and south poles of two permanent magnets. When current flows through the electromagnet, it becomes magnetized, and its poles are repelled by the like poles of the permanent magnets. This causes the electromagnet to turn toward the unlike poles of the permanent magnets. A device called a commutator then changes the direction of the current so the poles of the electromagnet are reversed. The reversed poles are once again repelled by the like poles of the permanent magnets. This causes the electromagnet to continue to turn. These events keep repeating, so the electromagnet rotates continuously. You can make a very simple electric motor with a battery, wire, and magnet following instructions at this URL: . 
 Question: part of an electric motor that changes the direction of the current

A:
commutator
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