Ecosystems
Gases that are soluble in water
Dissolved gases
Why is an overabundance of nutrients harmful to a water supply?
B. It causes excessive aquatic plant growth.
The majority of the elements on the periodic table are _______.
B.
metals
Animals that put all their weight on one toe are able to run more quickly across smooth, solid ground. Shortly after grasslands appeared, horses adapted to eating grass. How would running quickly probably have been an advantage to the horse's ancestors?
B. It allowed them to escape predators in large open spaces.
Viruses, bacteria, fungi, and parasites are all different types of infectious agents that may cause disease. What do these agents have in common?
A. They can all be spread from one organism to another.
the saltiness or amount of salt dissolved in a body of water
salinity
What is the most important reason that people should not drink directly from a river?
A.
The water might contain dangerous levels of harmful substances.
The rows of the periodic table are called _______.
A. periods
Some organisms have favorable traits that are well-suited to their environments. Organisms with this advantage are more likely to thrive, reproduce, and pass their traits to future generations than organisms without favorable traits.
This process is known as
D. natural selection.
A variety of microorganisms, including bacteria, viruses, fungi, and parasites, can cause specific diseases. What is most commonly used to fight these microorganisms?
B. medicine
Which of the following best describes why estuaries are important resources?
A. They are the world's richest sources of precious metals.
B. They prevent weathering of rock from slopes and cliffs.
C. They help stabilize the global climate.
D. They are among the most productive types of ecosystems.
D.
They are among the most productive types of ecosystems.
The Fish and Wildlife Commission is conducting research on fish populations in one of the nation's largest rivers. According to the research, fish numbers are steadily declining each year. If the scientists want to better understand what is happening to the fish, what measurement would yield the best data?
dissolved oxygen in the water
Which of the following is a nonmetal?
B. sulfur (S)
Index fossils are found throughout the world and come from organisms which existed during limited periods of geologic time. Which of the following best describes what index fossils can be used to determine?
C. the age of a layer of rock
Tucker has a rash on his foot. He thinks the rash is caused by a fungus, so he buys an over-the-counter antifungal medication and applies it exactly as directed. After a few weeks, the rash shows no sign of disappearing. What is the most likely reason for this?
D. The rash is not caused by a fungus.
The movement of water from one location to another
Ocean current
A wetland is any area that receives enough ground water or surface runoff to support plants and animals adapted to living in wet soil or standing water. North Carolina's wetlands are important because they
I.purify water to remove pollutants caused by human activites.II.hold surface runoff from developed areas and reduce flooding.III.are ideal for growing apples and peaches.IV.provide a place for migrating birds to stop and feed.
Which of the following elements is a highly reactive nonmetal?
A.
fluorine (F)
Which of the following is true about natural selection?
C. Natural selection usually causes a species to change gradually.
Which of these is a substance or compound that kills or inhibits bacteria?
D. an antibiotic
Of all the water found on Earth, how much of it is fresh water?
A.
about 3%
The health of any water system relies on the balance of many factors. Suppose a river's salinity (salt content) rises sharply due to construction projects on its banks. Which statement best predicts how such a change will affect the organisms that live in the river?
A. A number of organisms that live in the river might die depending on the severity of the rise.
Pure sodium metal (Na) is very reactive. It is usually stored in oil to prevent it from reacting violently with water vapor in the air. Based on the periodic table, which other metal is likely to be highly reactive?
B.
potassium (K)
Organisms with advantageous adaptations are more likely to survive and reproduce than organisms without the advantageous adaptations. This phenomenon is known as natural selection.
In order for natural selection to occur,
D.
organisms within a population must have some genetic variation.
Which statement about microorganisms is true?
D.
They all exhibit different forms and sizes.