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.

Context: The median age in the city was 35.1 years. 24.2% of residents were under the age of 18; 7.9% were between the ages of 18 and 24; 33.8% were from 25 to 44; 24.6% were from 45 to 64; and 9.5% were 65 years of age or older. The gender makeup of the city was 48.6% male and 51.4% females. 
 Question: Which age group is larger: under the age of 18 or 18 and 24?
under the age of 18

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
sebum

Context: When did you last visit a shopping mall? In many places, the answer would be "last weekend." Some people go even more often. Why? For one thing, malls offer goods and services that people need all in one place: food, clothing, things for their houses, entertainment, even medical services. So, are malls one of the highlights of modern civilization? Environmental activists would say No! They would go even further and say that consumer behavior is causing a huge environmental disaster. cause consumers of ignorance of the side effect of their shopping--urban sprawl . Social scientists agree that patterns of development have changed the landscape a great deal in the last half century. Before 1950, most people lived in towns or cities and either walked to work or took public transportation. Only very wealthy people had automobiles. Farmers lived in rural areas or isolated villages and came into town only when they needed things they couldn't produce themselves. If you gazed at the landscape you would see towns surrounded by countryside. Then a massive change occurred. Automobiles became affordable and people were quick to adopt them. Now ambitious workers could live in the suburbs, the areas just outside cities, which started to grow rapidly. As long as there was lots of cheap land in the suburbs, no one paid much attention to the usage of that land. Malls, fast food restaurants, cinemas, and car dealerships spread out in large, flat buildings. These one-storey buildings and their parking lot took up a great deal space. Well- meaning farmers thought they were better off selling their land than growing crops. In ignorance, no one realized that once the land was built up in urban sprawl, the good farming land would be ruined forever. There was no way to preserve it. Only in recent years have people come to mourn the old way of life as they have developed insight into the problems. Now people realize that urban sprawl has come with serious environmental problems. The negative aspects of sprawl include air and water pollution, loss of agricultural land, traffic jams, and the death of businesses in the old town centers. Many scholars think the time has come to analyze the problems better so we can develop appropriate policies to control further sprawl. Some think the best way to do is to educate citizens about their priceless environment. 
 Question: What is the scholars' attitude toward urban sprawl?

negative.