Science EOG Review 8th Grade

Earth's air is made up pf molecules of different gases that are not joined chemically. Which term best describes air?

• element

• compound

• mixture

• pure substance

Which statement best describe the periodic table?

• Each column forms a period

• The number of electrons decreases from the left to right

• The atomic mass dereases from the left to right

• Elements in the same group have similar chemical properties

Which of these elements is most likely to have chemical properties similar to those of calcium (Ca)?

• Magnesium (Mg)

• Neon (Ne)

• Potassium (K)

• Zirconium (Zr)

What percentage of Earth's surface is covered with water?

• 30 percent

• 50 percent

• 70 percent

• 90 percent

Which organism is most likely to be found near the ocean surface of the open ocean?

• whale

• clam

• crab

• snail

Which is a possible consequence of using hydro power to produce electricity?

• Dams may flood areas

• Radioactive waste may be produced

• air pollution may increase

• more fossil fuel may be used

What is the relationship between water temperature and dissolved oxygen?

• as water temperature increase, dissolved oxygen increase

• water temperature has no effect on the amount of dissolves oxygen

• dissolved oxygen decreases as water temperature decrease

• cold water contain more dissolved oxygen than warm water

Which is the bioindicator of water quality?

• diversity of insect larvae

• turbidity

• pH level

• salinity

Which term best describes an outbreak of flu that affects many people in a local area?

• vector

• pathogen

• epidemic

• pandemic

Which is least likely to show two species share a common ancestor?

• They have similar genetic sequences

• they have similar embryo development

• They have analogous body structure

• They have homologous body structure