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.

Ex Input:
Context: Biologists agree that the ancestor of mitochondria was an alpha-proteobacterium. But there is no consensus as to what constitutes an alpha-proteobacterial gene. Is it a gene found in all or several alpha-proteobacteria, or in only one? Here, we examine the proportion of alpha-proteobacterial genes in alpha-proteobacterial genomes by means of sequence comparisons. We find that each alpha-proteobacterium harbours a particular collection of genes and that, depending upon the lineage examined, between 97 and 33% are alpha-proteobacterial by the nearest-neighbour criterion. Our findings bear upon attempts to reconstruct the mitochondrial ancestor and upon inferences concerning the collection of genes that the mitochondrial ancestor possessed at the time that it became an endosymbiont. 
 Question: Which species of bacteria did the mitochondria originate from?

Ex Output:
biologists agree that the ancestor of mitochondria was an alpha-proteobacterium.


Ex Input:
Context: The endocrine system is a system of glands that release chemical messenger molecules into the blood stream. The messenger molecules are called hormones. Hormones act slowly compared with the rapid transmission of electrical impulses of the nervous system. Endocrine hormones must travel through the bloodstream to the cells they control, and this takes time. On the other hand, because endocrine hormones are released into the bloodstream, they travel to cells everywhere in the body. For a good visual introduction to the endocrine system, watch this short video: http MEDIA Click image to the left or use the URL below. URL: An endocrine gland is a gland that secretes hormones into the bloodstream for transport around the body (instead of secreting hormones locally, like sweat glands in the skin). Major glands of the endocrine system are shown in Figure 20.17. The glands are the same in males and females except for the ovaries and testes. The hypothalamus is actually part of the brain, but it also secretes hormones. Some of its hormones go directly to the pituitary gland in the endocrine system. These hypothalamus hormones tell the pituitary to either secrete or stop secreting its hormones. In this way, the hypothalamus provides a link between the nervous and endocrine systems. The hypothalamus also produces hormones that directly regulate body processes. For example, it produces antid- iuretic hormone. This hormone travels to the kidneys and stimulates them to conserve water by producing more concentrated urine. The pea-sized pituitary gland is just below the hypothalamus and attached directly to it. The pituitary receives hormones from the hypothalamus. It also secretes its own hormones. Most pituitary hormones control other endocrine glands. Thats why the pituitary gland is called the master gland of the endocrine system. Table Pituitary Hormone Adrenocorticotropic (ACTH) hormone Target Glands/Cells adrenal glands Thyroid-stimulating (TSH) Growth hormone (GH) hormone thyroid gland Follicle-stimulating (FSH) hormone body cells ovaries or testes Luteinizing hormone (LH) ovaries or testes Prolactin (PRL) mammary glands Effects(s) Stimulates the cortex (outer layer) of the adrenal glands to secrete their hormones Stimulates the thyroid gland to se- crete its hormones Stimulates body cells to make pro- teins and grow Stimulates the ovaries to develop mature eggs; stimulates the testes to produce sperm Stimulates the ovaries or testes to secrete sex hormones; stimulates the ovaries to release eggs Stimulates the mammary glands to produce milk There are several other endocrine glands. Find them in Figure 20.17 as you read about them below. The thyroid gland is a relatively large gland in the neck. Hormones secreted by the thyroid gland include thyroxin. Thyroxin increases the rate of metabolism in cells throughout the body. The pancreas is a large gland located near the stomach. Hormones secreted by the pancreas include insulin. Insulin helps cells absorb glucose from the blood. It also stimulates the liver to take up and store excess glucose. The two adrenal glands are glands located just above the kidneys. Each adrenal gland has an outer layer (cortex) and inner layer (medulla) that secrete different hormones. The hormone adrenaline is secreted by the inner layer. It prepares the body to respond to emergencies. For example, it increases the amount of oxygen and glucose going to the muscles. The gonads are glands that secrete sex hormones. Male gonads are called testes. They secrete the male sex hormone testosterone. The female gonads are called ovaries. They secrete the female sex hormone estrogen. Sex hormones stimulate the changes of puberty. They also control the production of sperm or eggs by the gonads. Endocrine hormones travel throughout the body in the blood. However, each endocrine hormone affects only certain cells, called target cells. A target cell is the type of cell on which a given endocrine hormone has an effect. A target cell is affected by a given hormone because it has proteins on its surface to which the hormone can bind. When the hormone binds to target cell proteins, it causes changes inside the cell. For example, binding of the hormone might cause the release of enzymes inside the cell. The enzymes then influence cell processes. Endocrine hormones control many cell activities, so they are very important for homeostasis. 
 Question: Which gland secretes growth hormone?

Ex Output:
pituitary gland


Ex Input:
Context: To describe your location wherever you are on Earths surface, you could use a coordinate system. For example, you could say that you are at 1234 Main Street, Springfield, Ohio. Or you could use a point of reference. If you want to meet up with a friend, you could tell him the distance and direction you are from the reference point. An example is, I am at the corner of Maple Street and Main Street, about two blocks north of your apartment. When studying Earths surface, scientists must be able to pinpoint a feature they are interested in. Scientists and others have a system to describe the location of any feature. Usually they use latitude and longitude as a coordinate system. Lines of latitude and longitude form a grid. The grid is centered on a reference point. You will learn about this type of grid when we discuss maps later in this chapter. When an object is moving, it is not enough to describe its location. We also need to know direction. Direction is important for describing moving objects. For example, a wind blows a storm over your school. Where is that storm coming from? Where is it going? The most common way to describe direction is by using a compass. A compass is a device with a floating needle (Figure 2.1). The needle is a small magnet that aligns itself with the Earths magnetic field. The compass needle always points to magnetic north. If you have a compass and you find north, you can then know any other direction. See the directions, such as east, south, west, etc., on a compass rose. A compass needle lines up with Earths magnetic north pole. This is different from Earths geographic north pole, or true north. The geographic north pole is the top of the imaginary axis around which Earth rotates. The geographic north pole is much like the spindle of a spinning top. The location of the geographic north pole does not change. However, the magnetic north pole shifts in location over time. Depending on where you live, you can correct for the difference between the two poles when you use a map and a compass (Figure 2.2). Some maps have a double compass rose. This allows users to make the corrections between magnetic north and true north. An example is a nautical chart that boaters use to chart their positions at sea (Figure 2.3). As you know, the surface of Earth is not flat. Some places are high and some places are low. For example, mountain ranges like the Sierra Nevada in California or the Andes in South America are high above the surrounding areas. We can describe the topography of a region by measuring the height or depth of that feature relative to sea level (Figure mountains, while others are more like small hills! Relief, or terrain, includes all the landforms of a region. A topographic map shows the height, or elevation, of features in an area. This includes mountains, craters, valleys, and rivers. For example, Figure 2.5 shows the San Francisco Peaks in northern Arizona. Features on the map include mountains, hills and lava flows. You can recognize these features from the differences in elevation. We will talk about some different landforms in the next section. If you take away the water in the oceans (Figure 2.6), Earth looks really different. You see that the surface has two main features: continents and ocean basins. Continents are large land areas. Ocean basins extend from the edges of continents to the ocean floor and into deep trenches. Continents are much older than ocean basins. Some rocks on the continents are billions of years old. Ocean basins are only millions of years old at their oldest. Because the continents are so old, a lot has happened to them! As we view the land around us we see landforms. Landforms are physical features on Earths surface. Landforms are introduced in this section but will be discussed more in later chapters. Constructive forces cause landforms to grow. Lava flowing into the ocean can build land outward. A volcano can be a constructive force. Destructive forces may blow landforms 
 Question: The terrain of an area, or the difference between high and low points in an area, is known as

Ex Output:

relief