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.

Example Input: 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: __major organ of the integumentary system
Example Output: skin

Example Input: Context: Epstein-Barr virus (EBV) is a highly prevalent virus, transmitted via saliva, which often causes asymptomatic infection in children but frequently results in infectious mononucleosis in adolescents. Heterophile antibody tests, including the Monospot test, are red cell or latex agglutination assays, which detect antired cell antibodies produced as part of a polyclonal antibody response occurring during EBV infection. Heterophile antibody tests are rapid, cheap and specific tests that can be performed from the onset of symptoms of infectious mononucleosis. In adolescents, heterophile antibody tests have high specificity and sensitivity in the diagnosis of primary acute EBV infection. However, the tests have low sensitivity and low negative predictive value in young children and are not useful under the age of 4. Heterophile tests may be positive in other viral infections, autoimmune disease and haematological malignancies, but do not appear to be positive in primary bacterial infection. Virus-specific serology is required in children under the age of 4 or if an older child is heterophile negative. Virus-specific serology allows diagnosis and the pattern of positivity and negativity enables the clinician to stage the EBV infection. Virus-specific serology appears to have better sensitivity in young children, but there is cross-reaction with other herpesvirus infections, a longer turnaround time and it is more expensive to perform. Further research is needed to establish which children benefit from and hence require testing for heterophile antibodies, the cost-effectiveness of EBV investigations and whether heterophile titres have predictive value for the severity of infection and the likelihood of complications. 
 Question: Which virus can be diagnosed with the monospot test?
Example Output: epstein-barr virus

Example Input: Context: Energy, or the ability to do work, can exist in many different forms. The photo in Figure 17.8 represents six of the eight different forms of energy that are described in this lesson. The guitarist gets the energy he needs to perform from chemical energy in food. He uses mechanical energy to pluck the strings of the guitar. The stage lights use electrical energy and give off both light energy and thermal energy, commonly called heat. The guitar also uses electrical energy, and it produces sound energy when the guitarist plucks the strings. For an introduction to all these forms of energy, go to this URL: . For an interactive animation about the different forms of energy, visit this URL: After you read below about different forms of energy, you can check your knowledge by doing the drag and drop quiz at this URL: . Mechanical energy is the energy of an object that is moving or has the potential to move. It is the sum of an objects kinetic and potential energy. In Figure 17.9, the basketball has mechanical energy because it is moving. The arrow in the same figure has mechanical energy because it has the potential to move due to the elasticity of the bow. What are some other examples of mechanical energy? Energy is stored in the bonds between atoms that make up compounds. This energy is called chemical energy, and it is a form of potential energy. If the bonds between atoms are broken, the energy is released and can do work. The wood in the fireplace in Figure 17.10 has chemical energy. The energy is released as thermal energy when the wood burns. People and many other living things meet their energy needs with chemical energy stored in food. When food molecules are broken down, the energy is released and may be used to do work. Electrons are negatively charged particles in atoms. Moving electrons have a form of kinetic energy called electrical energy. If youve ever experienced an electric outage, then you know how hard it is to get by without electrical energy. Most of the electrical energy we use is produced by power plants and arrives in our homes through wires. Two other sources of electrical energy are pictured in Figure 17.11. The nuclei of atoms are held together by powerful forces. This gives them a tremendous amount of stored energy, called nuclear energy. The energy can be released and used to do work. This happens in nuclear power plants when nuclei fission, or split apart. It also happens in the sun and other stars when nuclei fuse, or join together. Some of the suns energy travels to Earth, where it warms the planet and provides the energy for photosynthesis (see Figure The atoms that make up matter are in constant motion, so they have kinetic energy. All that motion gives matter thermal energy. Thermal energy is defined as the total kinetic energy of all the atoms that make up an object. It depends on how fast the atoms are moving and how many atoms the object has. Therefore, an object with more mass has greater thermal energy than an object with less mass, even if their individual atoms are moving at the same speed. You can see an example of this in Figure 17.13. Energy that the sun and other stars release into space is called electromagnetic energy. This form of energy travels through space as electrical and magnetic waves. Electromagnetic energy is commonly called light. It includes visible light, as well as radio waves, microwaves, and X rays (Figure 17.14). The drummer in Figure 17.15 is hitting the drumheads with drumsticks. This causes the drumheads to vibrate. The vibrations pass to surrounding air particles and then from one air particle to another in a wave of energy called sound energy. We hear sound when the sound waves reach our ears. Sound energy can travel through air, water, and other substances, but not through empty space. Thats because the energy needs particles of matter to pass it on. Energy often changes from one form to another. For example, the mechanical energy of a moving drumstick changes to sound energy when it strikes the drumhead and causes it to vibrate. Any 
 Question: total kinetic energy of all the atoms in an object
Example Output:
thermal energy