Explain a complex idea precisely

Grade 11 Reading Worksheet - Building Confidence

Circle the best answer.

1. Read this first

   How a Leaf Makes Sugar from Light (student informative essay draft)

   [1] Every green plant runs a chemical factory powered by sunlight, and the process it uses, called photosynthesis, turns two of the most ordinary substances into the sugar that the plant lives on. [2] Those two substances are carbon dioxide, a gas drawn in from the air, and water, which the roots absorb from the soil and send upward through narrow tubes in the stem. [3] The work takes place inside tiny green parts of the leaf's cells, where the light is captured and the chemical changes begin.

   [4] A leaf takes in carbon dioxide through stomata, which are small pores, usually more numerous on the underside of the leaf, that a pair of guard cells can open or close. [5] Inside the leaf, a green pigment called chlorophyll absorbs mostly red and blue light and reflects green light, which is why healthy leaves look green to our eyes. [6] This first stage, known as the light-dependent reactions, takes place on folded membranes called thylakoids, and it stores the captured energy in carrier molecules that the next stage can spend. [7] The oxygen that animals and people breathe is released during this stage as a by-product of splitting water, not from the carbon dioxide, as many readers assume.

   [8] The second stage, called the Calvin cycle, takes place in the fluid that surrounds the thylakoids, which is known as the stroma. [9] There, an enzyme called RuBisCO attaches carbon dioxide to an existing molecule, and the energy stored during the first stage is spent to build that carbon into sugar. [10] This second stage is the moment at which carbon that was floating in the atmosphere becomes part of a living thing.

   [11] The sugar a leaf builds does more than fuel the plant for a single day. [12] In that sense, much of a tree's trunk is built from carbon that was once a gas in the air around its leaves. [13] Photosynthesis also adds oxygen to the atmosphere while it removes carbon dioxide from it. [14] Understanding the two stages explains why a houseplant kept in a dark closet weakens even when it is watered, since water alone cannot become sugar without the energy of light.

2. 1.

   Ari sees a gap between [5] and [6]. Which sentence, placed there, builds on [5] and sets up "this first stage" in [6]?

   • Carbon dioxide reaches the inside of the leaf through the stomata, the pores that the guard cells control.
   • The energy of that absorbed light is used to split water molecules, and electrons freed from the water carry the energy on.
   • Chlorophyll takes in most of the red and blue light that reaches the leaf and sends the green light back out toward our eyes.
   • Water vapor escapes from a leaf through its stomata, especially on warm and dry afternoons.
3. 2.

   Bo wants a fact right after [11]. Which fact best supports the point that the sugar does more than fuel the plant for one day?

   • Plants also link sugar molecules into cellulose, the tough material of their cell walls, so the sugar becomes stems, leaves and wood.
   • Sugars of many different kinds are important substances in the lives of a great many living organisms.
   • Stomata close on hot, dry afternoons, which keeps a leaf from losing too much of its water as vapor.
   • The sugar a leaf makes is useful to the plant in a great many ways, well beyond the needs of a single day, as the plant keeps on growing.
4. 3.

   Sentence [3] says "tiny green parts of the leaf's cells." Esme wants the exact term. Which revision of [3] uses it?

   • The work takes place inside the leaf's remarkable cellular machinery, where the light is captured and the wondrous chemical changes begin.
   • The work takes place inside certain special components found deep within a leaf's cells, where the light is captured and the chemical changes begin.
   • The work takes place inside these little green thingies in a leaf's cells, where the light is captured and the chemical changes begin.
   • The work takes place inside chloroplasts, the small green structures in a leaf's cells, where the light is captured and the chemical changes begin.

5. Where the Morning Dew Comes From (student informative essay draft)

   [1] On a clear summer morning, the grass in a park can be soaked with water even though no rain fell during the night, and the water on each blade is called dew. [2] To understand where that water comes from, a reader needs to know that the air always holds some moisture as an invisible gas called water vapor. [3] Warm air can hold more water vapor than cool air before some of that vapor begins to turn back into liquid droplets.

   [4] The dew point is the temperature to which air must be cooled, without any change in its pressure or its moisture, before it becomes saturated with water vapor. [5] For that reason, forecasters often prefer the dew point to relative humidity, a percentage that rises and falls with the temperature even when the amount of moisture in the air stays the same.

   [6] On a clear, calm night, the ground and everything on it lose heat by sending invisible infrared radiation upward toward the sky, and very little of that heat comes back. [7] Grass cools especially quickly, because its thin blades stand apart from the warmer soil beneath them and gain little additional heat from it. [8] When the surface of a blade cools below the dew point of the air touching it, water vapor from that air begins to collect on the blade as tiny droplets. [9] The droplets grow larger through the night as more of the vapor in the air does its thing and becomes water. [10] When the surface is colder than freezing, the moisture collects as delicate ice crystals instead of liquid droplets, and the result is called frost.

   [11] Clouds and wind can keep dew from forming even on a night when the air is quite moist. [12] The dew point also offers a practical measure of how humid a summer afternoon will actually feel outdoors. [13] One National Weather Service office describes summer dew points of 55 degrees Fahrenheit or lower as dry and comfortable, and dew points of 65 degrees or higher as oppressive. [14] Understanding the dew point therefore explains both the wet grass of a clear morning and the heavy, sticky feeling of a muggy afternoon.

6. 4.

   Jun sees a gap between [4] and [5]: "For that reason" has no reason. Which sentence, placed there, builds on [4] and sets up [5]?

   • Because moister air becomes saturated sooner as it cools, a higher dew point means that the air is holding more water vapor.
   • Dew is especially common in late summer, and it often coats car roofs and railings as well as grass.
   • Water vapor is an invisible gas, and the air usually contains at least a little of it.
   • When a blade of grass cools below the dew point of the air around it, droplets of water begin to collect on its surface overnight.
7. 5.

   Kira wants a fact right after [11]. Which fact develops the point of [11] most usefully?

   • Clouds send infrared radiation back toward the ground, and wind mixes warmer air down onto the grass, so the blades never cool to the dew point.
   • Many different kinds of weather can change what a person finds outdoors early in the morning.
   • A cloudy or windy night can leave the grass dry by morning, even when the air has plenty of moisture in it.
   • Shiny metal surfaces tend to collect less dew than grass or wood, because they give off infrared radiation poorly.
8. 6.

   Sentence [9] says the vapor "does its thing and becomes water." Luz wants the exact term. Which revision of [9] uses it?

   • The droplets grow larger through the night as more of the vapor in the air condenses, changing from a gas into liquid water.
   • The droplets grow larger through the night as more of the vapor in the air evaporates, changing from a gas into liquid water.
   • The droplets grow larger through the night as more of the vapor in the air gets turned into actual water stuff.
   • The droplets grow larger through the night as more of the vapor in the air undergoes a quiet and wondrous transformation into water.

9. Dots, Dashes and a Wire (student informative essay draft)

   [1] Before the telegraph, a message could travel no faster than the horse, ship or train that carried it, so news from a city a few hundred miles away could take days to arrive. [2] The electrical telegraph changed that by sending a message as pulses of electric current along a wire, and the pulses reached the far end almost at the moment they were sent. [3] In 1843, Congress gave Samuel Morse thirty thousand dollars to build an experimental line between Washington, D.C., and Baltimore, and the line officially opened in May 1844.

   [4] The sending end of the line had a key, a spring-loaded lever that closed an electric circuit while the operator held it down and opened the circuit when the operator let go. [5] At the receiving end, each pulse of current switched on a small device. [6] That device pulled a metal arm toward it, and the arm made a mark or a click, so the receiving operator could tell a short pulse from a long one. [7] Morse and his partner, Alfred Vail, therefore needed a code that could spell out words using nothing but those two lengths of signal. [8] Vail estimated how often each letter was used by counting the pieces of type in a newspaper's printing office, and the most common letters received the shortest patterns. [9] That is why the letter E, the most common letter in English, is a single dot, while the letter T is a single dash.

   [10] Timing mattered as much as the marks themselves. [11] An operator who rushed the pauses could run two letters together, and the receiver would then read a different word from the one the sender intended.

   [12] By 1866, a lasting cable laid under the Atlantic Ocean had joined the telegraph networks of North America and Europe. [13] Newspapers, railroads and businesses soon came to depend on information that arrived within minutes rather than days. [14] The code is rarely used for everyday messages today, yet its central idea, sending information as a pattern of signals switched on and off, is close to the idea beneath modern digital communication.

10. 7.

    Milo sees a gap between [7] and [8]. Which sentence, placed there, builds on [7] and sets up "the shortest patterns" in [8]?

    • The code had to spell out words with two lengths of pulse and no other kind of signal.
    • That is the reason the letter E became a single dot, since E appears in written English more often than any other letter of the alphabet.
    • The key at the sending end closed the circuit whenever the operator pressed the lever down.
    • In the code they developed, each letter became its own pattern of short signals, called dots, and long signals, called dashes.
11. 8.

    Noah wants a fact right after [10]. Which fact best supports the point that timing mattered as much as the marks?

    • The key was a spring-loaded lever, so it opened the circuit again as soon as the operator let go.
    • In International Morse Code, the later standard version, a dash lasts three times as long as a dot, and the pause between letters also lasts three dots.
    • Morse helped found the National Academy of Design in 1826, years before he built his first telegraph line.
    • Any system of signals depends on its users agreeing about its rules.
12. 9.

    Sentence [5] says each pulse "switched on a small device." Pia wants the exact term. Which revision of [5] uses it?

    • At the receiving end, each pulse of current switched on a certain electrical mechanism that responded whenever current arrived along the wire.
    • At the receiving end, each pulse of current switched on an electromagnet, a coil of wire that becomes magnetic while current flows through it.
    • At the receiving end, each pulse of current switched on a little magnet gizmo that reacted when the current showed up.
    • At the receiving end, each pulse of current switched on a battery, a coil of wire that becomes magnetic while current flows through it.

13. How a Lock Lifts a Ship (student informative essay draft)

    [1] A canal that crosses hilly country cannot simply run uphill, so engineers divide it into level stretches, like the steps of a staircase, and connect the steps with structures called locks. [2] A lock is a watertight chamber with a gate at each end, long and wide enough to hold a boat while the level of the water inside it is changed. [3] When a boat traveling upstream enters the chamber from the lower level, the gate behind it closes, and the chamber is sealed. [4] Once the water inside matches the level ahead, the upper gate can be swung open with little effort, and the boat continues on its way. [5] Going downstream is the same process in reverse, as water is released from the chamber to the lower level until the boat settles gently to match it.

    [6] Most locks need surprisingly little power to move enormous ships. [7] Motors are used for smaller jobs, such as swinging the gates and opening the valves that let the water in or out.

    [8] The gates themselves are shaped to use the force of the water rather than to fight against it. [9] Most canal locks use a pair of doors that meet at an angle, pointing upstream, so that from above they form a shallow V. [10] The pressure of the higher water pushes the two gates more tightly against each other, much as the stones of an arch press together, so the higher the water rises, the more firmly the gates seal. [11] This arrangement is generally credited to Leonardo da Vinci, who is believed to have designed it in the late fifteenth century.

    [12] The largest locks raise ships to great heights by linking several chambers in a row. [13] The original locks of the Panama Canal lift ships about eighty-five feet, from sea level to the surface of Gatun Lake, in three steps on each side of the canal. [14] Every lockful of water flows downhill and eventually out to sea, so a canal that makes a long climb depends on a steady supply of water at its highest level, often from a lake or a reservoir.

14. 10.

    Tala wants a fact right after [6]. Which fact best supports the point that locks need little power to move enormous ships?

    • Lifting a huge ship with very little power is one of the most impressive things about a lock.
    • In the Panama Canal, the water that fills each chamber flows by gravity through large tunnels in the walls and floor, so no pumps lift the ships.
    • The Panama Canal opened in 1914, and ships from many nations have used it ever since.
    • The gates of a lock meet at an angle, so the pressure of the higher water presses them closed.