8th Grade Science EOG Review #1

The table shows four examples of interactions between two organisms.

Which examples represent parasitic relationships?

• A. 1 and 3

• B. 1 and 4

• C. 2 and 3

• D. 2 and 4

A teacher asks her students to classify the substances listed in the table shown as elements, compounds, or mixtures.

A student claims that all of the substances are compounds. Which statement correctly describes the student’s claim?

• A. The student’s claim is correct because a substance that contains more than two of the same atom is a compound.

• B. The student’s claim is incorrect because a substance that contains more than one element is always a mixture.

• C. The student’s claim is incorrect because the atoms in the substances are physically combined to form a mixture.

• D. The student’s claim is correct because the atoms in the substances are chemically combined to form a compound.

What makes 97% of the water on Earth unfit for drinking?

• A. It is highly saline.

• B. It is frozen.

• C. It has a low density.

• D. It has a high specific heat.

Examine the information showing the aquatic fish and plant species found in a lake and their pH tolerances.

A researcher measures the pH of the lake water as 5.3. Which conclusion correctly describes the effect on aquatic species if additional acidic water is released into the lake?

• A. The pH of the lake will increase, making the water less suitable for the survival of trout.

• B. The pH of the lake will increase, making the water more suitable for the survival of water lilies.

• C. The pH of the lake will decrease, making the water more suitable for the survival of salmon.

• D. The pH of the lake will decrease, making the water less suitable for the survival of plankton.

Which step of water treatment requires an addition of chlorine?

• A. aeration of water

• B. disinfection of water

• C. filtration of impurities

• D. sedimentation of impurities

The graph shows the percentage of crops pollinated by honey bees in the United States.

It has been estimated that more than 10 million beehives were lost in 2013 in the United States due to colony collapse disorder caused by the widespread use of pesticides. How will the decrease in the honey bee population affect the ecosystem?

• A. It will increase the percentages of almond and apple crops because insects other than honey bees will help pollinate these crops.

• B. It will increase the percentages of cotton and orange crops because these are less dependent on honey bee pollination.

• C. It will decrease the percentages of almond and apple crops because lesser numbers of honey bees are available for pollination.

• D. It will decrease the percentages of cotton and orange crops because the populations of other insects will also decline along with honey bees.

A student places a piece of magnesium metal in a test tube containing acid. The student records four observations during the experiment.

Which observation describes a chemical change?

• A. #1

• B. #2

• C. #3

• D. #4

The diagram shows the temperature variations in two regions (X and Y) as ocean depth increases.

Which statement correctly describes the behavior of dissolved gases in each of the two regions?

• A. Region Y would contain more dissolved gases than region X as the water is deeper and colder.

• B. Region X would contain more dissolved gases than region Y as the water is deeper and colder.

• C. Region Y would contain more dissolved gases than region X as the water is shallower and warmer.

• D. Region X would contain more dissolved gases than region Y as the water is shallower and warmer.

A student makes a model to demonstrate a functioning ecosystem by filling a glass jar with water and adding two goldfish and two butterfly fish. The student’s teacher says that the model could be improved.

What should the student do to improve the model?

• A. The student should add more goldfish or butterfly fish to the jar.

• B. The student should keep the glass jar in sunlight.

• C. The student should change the water of the jar daily.

• D. The student should add small rocks and aquatic plants to the jar.

Examine the map that shows the river basins of North Carolina and a star that indicates the location of a farm with runoff containing excess nitrates and phosphates.

Which city(ies) need(s) to be concerned with potential algal blooms caused by the excess nitrate and phosphate pollution, and why?

• A. Fayetteville; the pollution will only affect the city that is closest to the source.

• B. Raleigh and New Bern; the pollution will travel both upstream and downstream within the river basin.

• C. New Bern; the pollution will only travel downstream within the river basin.

• D. Fayetteville and Wilmington; the pollution will travel directly south regardless of the river basin in which the source is found.