Science
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39 Alpha Centauri appears as a bright object visible in the Milky Way
galaxy. Alpha Centauri is actually a system of three objects. Each
object produces light and rotates on its own axis. The system is an
average of 4 light-years from Earth.
Based on this information, the three objects that make up the
Alpha Centauri system are all —
A asteroids
B comets
C planets
D stars
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40 Students performed a lab investigation on chemical reactions. The
students put on goggles and plastic gloves and then followed these
steps.
1. Pour 150 milliliters of vinegar into a beaker.
2. Place a thermometer in the vinegar and record
measurements.
3. Add a piece of steel wool to the beaker.
4. Observe and record thermometer
measurements.
5. Remove the steel wool from the beaker.
6. Use tweezers to pull strands of the steel wool
apart and observe changes.
Which observation would indicate that a chemical reaction
occurred?
F The vinegar took the shape of the container in step 1.
G The steel wool sank into the vinegar in step 3.
H The temperature of the vinegar increased during step 4.
J The steel wool changed shape during step 6.