Researchers grew some bacteria in a lab and tested them in several trials. The results are shown in the table.
In this experiment, which trial served as the control?
Scientists conduct many types of scientific investigations. Their efforts often include fieldwork, surveys, models, and experiments. Which statement about scientific investigations is not true?
They often involve the collection of data under controlled conditions.
They often include multiple trials to increase the consistency of data.
They may focus on comparing or describing the natural world.
They follow exactly the same steps because there is only one scientific method.
Students made an electromagnet by wrapping a wire in loops around an iron nail and attaching the wire to a battery, as shown below.
The students conducted a test to learn how the number of wire loops affected the number of paper clips held by the electromagnet. The table below shows the results of the test.
Based on the information from the table, which of the following is the test (independent) variable in this experiment?
size of the nail
number of paper clips held
number of wire loops
size of battery
Ginger hypothesized that she could use a screen to separate a mixture of sugar and sand. When she tried this method, she was not able to separate the mixture. Although her hypothesis was not correct, why was it still valuable?
It gave her the opportunity to conduct an experiment that had a hypothesis.
It allowed her to rule out that method and try another investigation.
It was an important part of the scientific method which must be used in every investigation.
It helped her to figure out that it is not possible to separate a mixture of sugar and sand.
Shawna did an experiment to study the rate of photosynthesis in the water plant Elodea. She placed a piece of Elodea in a beaker of water and set the beaker 10 centimeters from a light source. Shawna counted the bubbles released from the plant every minute for five minutes. She repeated the process two more times. First, she moved the light to 20 centimeters from the beaker, and then she moved the light to 30 centimeters from the beaker. Shawna’s setup and data are shown below.
What is the outcome (dependent) variable in this experiment?
the amount of time the bubbles were counted
the distance of the light source from the plant
the number of bubbles produced
the type of plant placed in the beaker
Cathy designs an experiment to investigate how well cups made of different materials maintain the temperature of a cold drink. Which step will increase the accuracy and validity of Cathy’s results?
Use a different beverage in each cup.
Conduct the experiment in a cool room.
Conduct multiple trials and have another scientist repeat the experiment.
Analyze the experimental results and organize experimental data in a table.
Dan uses a thermometer to measure the temperature of alcohol in a beaker. He heats the beaker for 1 minute and measures the temperature again. The temperature increases by 10 degrees. Which of the following experiments replicates Dan’s experiment?
John repeats Dan’s experiment, but he replaces the alcohol with water.
Sue repeats Dan’s experiment, and the temperature increases 10 degrees.
Dan performs the experiment again, and the temperature increases by 12 degrees.
Dan heats another beaker of alcohol for 1 minute and measures the temperature before and after heating.
If a scientist does an experiment but no one else can get the same results when they replicate the scientist’s experiment, what does that mean?
We should assume everyone else did the experiment incorrectly.
We should conclude he is a better scientist than the others.
We should not trust the results of the original experiment.
We should assume the notes he kept on his experiment were incomplete.
A biologist is studying the migratory behavior of a species of sharks. Which is the best method the biologist could use in the study?
Develop a theory for why the sharks behave a certain way.
Collect data by observing the behavior of the sharks in the wild.
Design a controlled experiment to test the behavior of the sharks.
Create a prediction of sharks' behavior by using other scientists' data.
Janine is learning about how waves in the ocean form and move. For a class assignment, she builds a wave machine using a glass jar, water, mineral oil, and food coloring. Which best describes how Janine's model helps her to learn about waves?
It lets her observe wave motion without having to be near the ocean.
It helps her describe the differences between types of ocean waves.
It allows her to explain how weather affects the formation of ocean waves.
It shows all the microscopic parts of the wave she couldn't normally see.
A controlled experiment is a means for carrying out a fair test of a hypothesis. In a controlled experiment, all of the variables that can influence the outcome variable (dependent variable) of the experiment are controlled or held constant, except for the test variable (independent variable). Which of the following hypotheses would NOT be tested using a controlled experiment?
A geologist’s hypothesis about how the Grand Canyon formed.
A biologist’s hypothesis that use of fertilizer increase the growth of grass.
A biologist’s hypothesis that increases in average temperatures causes an increase in honey bee population.
A geologist’s hypothesis that acid rain weathers sedimentary rock more rapidly than igneous rock.
Scientists use many different methods of investigation. When possible, scientists want to actually experiment or observe an event. Which method is useful when developing a scientific explanation for a system that cannot be studied directly?
Conduct a field survey of the system.
Observe the effect of independent variables in the system.
Use a computer model to study the system.
Measure chosen variables of the system.
A scientist is researching the solar system. How can the scientist best add to the empirical evidence already gathered about the solar system?
The scientist can make and record observations.
The scientist can debate the research with other scientists.
The scientist can write an opinion column about the research.
The scientist can develop a new law regarding the solar system.
When Alfred Wegener first proposed his theory of continental drift, most Earth scientists did not immediately accept it. Many expressed skepticism because the theory did not explain what force was strong enough to move continents. Later, scientists investigating continental drift found evidence that explained how continents are able to move. Plate tectonics, which grew from the theory of continental drift, now explains how continents move over time. Which statement is true?
Skeptical comments showed that continental drift was not a correct explanation of Wegener’s observations.
The skeptics kept people from forgetting about earlier observations that did not support continental drift.
The scientists who were skeptical kept earth science from changing views too rapidly.
The skeptics raised questions that became the starting point for new investigations.
What would NOT be empirical evidence that the moon orbits the Earth every 27.3 days?
Scientists observe the phases of the moon.
Scientists use images from space to see the moon orbiting the Earth.
Scientists measure the distance the moon travels as well as its speed as it orbits the Earth.
Scientists read myths that explain the moon’s phases.
The law of universal gravitation states that both mass and distance of objects affect the gravitational force between them. Gravitational force increases as the mass of the objects increase. Gravitational force decreases as distance between the objects increases. Why are these statements considered scientific law, and not scientific theory?
The statements describe what happens, and not why the event occurs.
This statement involves mass and distance measurements.
This statement explains the attractive force between two objects
This statement predicts what will happen under certain conditions.
Corrine is studying the theory of evolution. She asks her teacher if the theory of evolution will ever become the law of evolution. Her teacher tells her that it will not. Why can a scientific theory not become a scientific law?
Laws are proven and theories are unproven.
Laws are generally accepted rules about phenomena and theories are explanations of observations.
Laws are educated guesses, while theories are yet to be tested.
Laws are always true and theories are sometimes true.
In the 1860s, Charles Darwin proposed the theory of evolution. His theory stated that populations change very slowly over a very long period of time. Then in 1972, some scientists took a closer look at the fossil record. They concluded that evolution involves long periods of little change in populations which are interrupted by short periods of rapid change. This finding became part of the theory of evolution. What can you conclude from this information?
New evidence can cause a scientific theory to be modified.
New evidence can cause a scientific theory to be discarded.
New evidence can cause a scientific theory to become a law.
New evidence can cause a scientific theory to change into a new theory.
A physician specializes on surgery involving the esophagus, stomach, and intestines. This physician is specialized at which level of organization.
Humans and other complex organisms have a hierarchical system of organization. Which of the following statements is true regarding this system of organization?
Atoms are made of cells.
Organs are made of organ systems.
Cells are made of tissues.
Organs are made of tissues.
The diagram shows parts of the human body. These parts work together to help you digest the food you eat.
Which term best describes the entire group of parts that are labeled?
The cell theory is one of the unifying themes of biology. Which of the following is NOT one of the main components of the cell theory?
cells must contain DNA
all living things are made of cells
cells can only come from other cells
cells are the basic unit of life
Some organisms have one cell. Other organisms have multiple cells. Which of the following is a characteristic of cells in a multicellular organism?
All cells have the same function.
Every cell has a different function.
Different kinds of cells have the same function.
Different kinds of cells have different functions.
A cell needs to maintain a certain amount of water within it. The ability of the cell to maintain the stable internal condition is called _____________.
Under a high-powered microscope, Dan sees a cellular organelle. His teacher tells him that this organelle is called the “powerhouse,” of the cell. Which organelle does Dan see?
You are told that the cells on a microscope slide are plant, animal, or bacterial. You look at them through a microscope and see cell walls and chloroplasts. You conclude that the cells
are plant cells.
could be either plant or animal cells
are animal cells
are bacterial cells
Which ONE of the following correctly matches the organelle with its function?
cytoplasm: produces energy for the cell
nucleus: control center of the cell
cell membrane: gives rigid structure to the plant cell
vacuoles: colorless, jelly-like substance that supports the other organelles
Which of the following describes the relationship between chloroplasts and mitochondria?
Mitochondria produce sugar (glucose), and chloroplasts use this sugar to make energy (ATP).
Chloroplasts produce sugar (glucose), and mitochondria use this sugar to make energy (ATP).
Mitochondria produce the enzymes that chloroplasts need to carry out photosynthesis.
Chloroplasts produce the proteins that mitochondria need to perform cellular respiration
Julia is learning about the nervous system in school. She learns the nervous system is made up of many parts.What is the main purpose of the nervous system in the human body?
relaying messages between the body and brain
circulating oxygen throughout the body
releasing hormones to regulate body functions
protecting the body from foreign invaders
Which of the following best explains the interaction between the digestive system and the respiratory system?
To use the energy in food broken down by the digestive system, the body needs oxygen obtained by the respiratory system.
The main function of the respiratory system is to control, coordinate, and regulate most of the functions of the digestive system.
Coordination between the respiratory and digestive systems is necessary because the digestive system obtains oxygen needed by the respiratory system.
The digestive system obtains nutrients from the food that is eaten, and the respiratory system transports the nutrients to the brain where they are needed.
Which series includes three pathogens that cause infectious diseases?
viruses, bacteria, and mutagens
bacteria, fungi, and parasites
mutagens, viruses, and bacteria
parasites, mutagens, and fungi
Viruses cause many human diseases. A virus is a strand of DNA or RNA surrounded by a layer of protein. Viruses can replicate
when they become a certain size.
when they grow to a certain number of cells.
only after infecting a host cell.
only after they mutate.
In 1990, Carl Woese introduced the three domain system for classifying living things, after the
advancement of DNA analysis allowed for a comparison of species genetic code. Which of the following is the best explanation for why domains were added to the previous system of classification?
The old system of classification was wrong and needed to be corrected.
New species are evolving too quickly to keep up with the old system of classification.
Domains have always been included; they were just made official recently.
Some organisms, which were previously characterized together, were determined to be genetically very different.
Felicia’s teacher gives her the following list of organisms:
1. Multicellular organism that has cells with cell walls and makes its own food
2. Multi-cellular organism with cell wall that absorbs food from its environment
3. Single-cellular organism with nucleus that makes its own food
4. Multicellular organism that gets food by eating other organisms
Felicia needs to identify the kingdom for each organism. In what order should she list the kingdoms for organisms 1 through 4?
Plantae, Fungi, Protista, Animalia
Animalia, Protista, Plantae, Fungi
Plantae, Protista, Fungi, Animalia
Fungi, Plantae, Protista, Animalia
Penelope wants to identify the characteristics that each of four organisms have in common. She uses the following table to help in the identification process.
Which organism should she identify as having the least in common with the other organisms?
According to the theory of natural selection, what would happen to a species of lizards when a new predator is introduced into the environmnet where the lizards live?
The lizards that already have the physical traits needed to avoid the new predator would be more likely to survive and reproduce, and the ones that do not would be less likely to survive and reproduce.
All of the lizards would try to develop new physical traits to avoid the new predator.
Some of the lizards would try to develop new physical traits to avoid the new predator, and the other lizards would die.
Because all lizards of the same species have the same physical traits, one lizard would not have an advantage over another lizard. They would either all survive or die.
Elephants are the largest land animals alive today. They are the only mammals to have four knees. Evidence of extinct woolly mammoths shows that they shared the trait of having four knees, but they were not African or Asian elephants. How could the mammoths and elephants share this characteristic?
Today's elephants are clones of the woolly mammoths.
Elephants and woolly mammoths had a common ancestor.
Today's elephants have adapted to look like woolly mammoths.
Woolly mammoths are one of the three species of today’s elephants.
A certain reptile species is a herbivore and exists only on an isolated island. Which of the following would most likely result in the extinction of the reptile species over a period of twenty thousand years?
The reptile species produces many offspring with many unique traits, and the vegetation remains constant.
The reptile species produces few offspring with some unique traits, and the vegetation remains constant.
The reptile species produces few offspring with no unique traits, and the vegetation changes quickly.
The reptile species produces many offspring with some unique traits, and the vegetation changes slowly.
Genes, chromosomes, and DNA are important structures for processes related to heredity and reproduction . How are these three structures related?
Genes are sections of DNA that make up a chromosome.
Many chromosomes make up a gene, and many genes make up DNA.
A chromosome is the same thing as a gene, and both are made of DNA.
DNA is made up of chromsomes, and chromsomes are made up of genes.
Is there a genetic difference in the daughter cells produced during mitosis and meiosis?
No, during mitosis and meiosis the daughter cells are genetically the same.
No, during mitosis and meiosis the daughter cells are genetically different.
Yes, during mitosis and meiosis the daughter cells are genetically different in mitosis but genetically the same in meiosis.
Yes, during mitosis and meiosis the daughter cells are genetically different in meiosis but genetically the same in mitosis.
The trait for a dimples (D) is dominant over the trait for no dimples (d). Two people with dimples (Dd x Dd) got married. Complete the diagram below to show the genes of their children. What percentage of the offspring will most likely have no dimples?
Look at the diagram below.
Assume that shaded individuals have the alleles gg. Which of these statements is true about the alleles of individual 2 in generation II?
Individual II-2 must have the alleles GG.
Individual II-2 must have the alleles Gg.
Individual II-2 must have the alleles gg.
Individual II-2 could have either the alleles Gg or the alleles gg.
Veronica discovers a new plant in a forest. She observes it for some time, and when it reproduces, she tests the offspring and finds that they are genetically identical to the parent. Which of these statements is true about Veronica’s find?
The plant reproduces sexually, and two parents are required.
The plant reproduces asexually, and two parents are required.
The plant reproduces sexually, and only one parent is required.
The plant reproduces asexually, and only one parent is required.
A spider hides in an orchid flower. It captures and eats insects as they enter the flower. In which case could this be an example of mutualism between the spider and the orchid plant?
if the spider is also eating part of the flower
if the spider’s actions do not affect the orchid plant
if the insects that the spider captures are harming the flower
if the insects that the spider captures are pollinating the flower
Scientists studied predator-prey relationships in a habitat. The diagram below shows the
feeding relationships among organisms in a certain environment.
Which animal is both a predator and prey?
In a pond, the primary producer is a green algea, spirogyra; the primary consumer is the crustacean, daphnia; the secondary consumer is a small fish, the bluegill; and the tertiary consumer is a larger fish, the smallmouth bass. What changes can be expected in the pond if the daphnia are killed with pesticides?
The spirogyra population will probably die.
The bluegill population will probably decrease.
The daphnia population will eat something else.
The smallmouth bass population will increase.
The diagram below shows a food web for a mangrove swamp ecosystem.
In this ecosystem, what organisms compete for the same resources?
mangrove and small fish
prawn (shrimp) and phytoplankton
prawn (shrimp) and pelican
heron and pelican
Which process occurs inside plant and animal cells and releases energy from glucose for the cell to use for cellular functions?
In the process of photosynthesis, plants use carbon dioxide, water, and energy to form carbohydrates and oxygen. Which of the following best explains how plants follow the Law of Conservation of Mass during photosynthesis?
The reaction uses energy to produce a product without energy.
A gas (carbon dioxide) and a liquid (water) use energy to produce a solid (carbohydrates).
The amount of each element that begins photosynthesis equals the amount of each element that is produced.
The amount of carboydrates at the beginning of photosynthesis equals the amount of oxygen that is produced.
A diagram of the carbon cycle is shown below.
Which of the following best explains the roles plants and animals play in recycling carbon?
Plants and animals both take in carbon through respiration. They return it to the cycle through decomposition.
Plants take in carbon through photosynthesis and decomposition. Animals produce carbon through respiration.
Animals produce carbon through exhaling. Plants take in carbon for photosynthesis.
Plants produce carbon through photosynthesis. Animals take in carbon for breathing.
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