(1) Some libraries now set aside one loud room. (2) Group projects require talking. (3) At Ridgeway, teams rehearse presentations in the glass room each afternoon. (4) Upper floors stay silent. What job does sentence 3 do?

(1) Sea otters eat sea urchins. (2) Urchins graze kelp down to stumps. (3) Where otters returned, kelp forests grew back within a decade. (4) One predator can decide whether a kelp forest survives. Which sentence states the paragraph's key concept?

(1) Builders in flood zones now add freeboard. (2) Freeboard is extra height built above the required flood level. (3) An extra foot of it kept the Marsh Street shops dry last spring. (4) The added cost is small. What does sentence 2 do?

(1) Later school start times help teenagers sleep. (2) Districts that moved to 8:30 report fewer late arrivals. (3) Still, one bus loop serves three schools, so a later start strands younger riders. (4) Routes can be redrawn. What does sentence 3 do?

(1) Streetlights near the shore glow all night. (2) Hatchling turtles crawl toward the brightest light. (3) On lit beaches, many hatchlings turn inland instead of seaward. (4) So shore lighting decides where a hatchling goes. What does sentence 4 do?

(1) Those early maps were guesses, but the next century brought measurement. (2) Surveyors dragged marked chains across open fields. (3) Each chain length was recorded and summed. (4) Errors shrank to inches. What role does sentence 1 play?

(1) Bees find flowers by scent and by color. (2) Many petals reflect ultraviolet patterns people cannot see. (3) Hives near mixed gardens produce more honey. Where does this sentence best belong? "To a bee, a plain yellow petal may look striped."

(1) Rain gardens soak up runoff from driveways and roofs. (2) A gravel base holds water while it sinks in. (3) They work only where soil drains; over heavy clay, water sits for days. (4) Cities map soils first. What does sentence 3 do?

(1) The first steam ferries burned wood. (2) Crews stopped every few hours for more. (3) Fuel, not engine power, set the limits of early steam travel. (4) Coal changed that, packing more heat into less space. Which sentence states the main point?

(1) Rooftop gardens cool the buildings under them. (2) Plants shade the roof and release water into the air. (3) A survey of forty buildings found planted roofs stayed cooler on summer afternoons. (4) Roofs need reinforcing first. What does sentence 3 do?

(1) Many desert plants store water in thick stems. (2) A saguaro swells after rain and slowly shrinks. (3) Mesquite does the opposite, sending roots deep to reach groundwater. (4) Both habits help plants survive drought. What does sentence 3 do?

(1) Museums once bolted every artifact behind glass. (2) Handling copies lets visitors feel weight and texture. (3) At one history center, replica tools travel the halls on carts. (4) Touch teaches what a label cannot. What does sentence 4 do?

(1) Volunteers count monarchs each fall. (2) A cold snap grounds thousands for days, so one total proves little. (3) Twenty years of counts show a decline. Where does this sentence best fit? "Each counter walks a fixed route and records every butterfly."

(1) Snails clamp down as the water drains. (2) Crabs wedge under wet rock. (3) Anemones fold their tentacles in. (4) Each buys hours until the tide returns. Where does this sentence best fit? "Tide pool animals survive low tide by holding water close."

(1) A city audit listed every broken streetlight. (2) Crews repaired the darkest blocks first. (3) Night crashes on those blocks fell the following year. Where does this sentence best belong? "The audit is now repeated every spring."

(1) Wildfire smoke drifted hundreds of miles east last summer. (2) Smoke rides the jet stream, a fast current of air high above the ground. (3) Cities far from any fire logged unhealthy air. (4) Distance no longer means safety. What does sentence 2 do?

(1) Night noise wakes hospital patients. (2) Alarms, carts, and hallway talk carry through doors. (3) Records from one ward show patients on quiet nights went home sooner. (4) Quiet is treatment, not courtesy. Which sentence supplies the evidence?

(1) Bridges are built with gaps at each end. (2) Steel expands in heat and contracts in cold. (3) Without those gaps, a hot afternoon would buckle the deck. (4) Drivers hear the joints as a thump. What does sentence 2 do?

(1) Community fridges hold donated food on sidewalks. (2) The first one here was painted yellow. (3) Anyone may take what they need, with no form or line. (4) The aim is to remove every barrier. Which sentence contributes least to the key concept?

(1) Public benches now come with center armrests. (2) Designers call them dividers; critics call them barriers to sleeping. (3) Either way, the bar decides who may lie down. (4) A few parks have removed them. What does sentence 3 do?