Nicholas is conducting an investigation to determine how the number of turtles in a pond changes over several months. Which of the following would be the best way for Nicholas to organize and show his data?

Jacob conducted an investigation to determine the effect of acid on different types of rocks. He found that the data he collected do not support his hypothesis. Why would Jacob's hypothesis still have some value?

A prokaryote is a one-celled organism that does not have a nucleus. The cells of plants, animals, and other eukaryotes do have a nucleus. They also have organelles called mitochondria and chloroplasts. In the 1960s, the scientist Lynn Margulis proposed a theory about mitochondria and

chloroplasts. Her theory states that they developed from ancient prokaryotes that were taken in by larger cells. The prokaryotes lived inside the larger cells and helped them survive. For example, some of the prokaryotes made food for the cells by photosynthesis. Over time, the prokaryotes inside the cells became mitochondria and chloroplasts.

Many were skeptical of Margulis's theory when she first proposed it. Since that time, scientists have used new technologies to gather data that support the theory. The table shows some of these data.

Which of the following observations best supports Margulis's theory?

Isabella used litmus paper to study acids and bases. Blue litmus paper turns red when exposed to an acid. Red litmus paper turns blue when exposed to a base. Isabella tested vinegar with blue and red litmus paper. She concluded that vinegar is an acid. Which of the following most likely describes the observations that Isabella made when she tested the vinegar?

Dr. Rodriguez conducts an investigation to test her ideas about what causes tornadoes to form. She shares the results of the investigation with other scientists, who then replicate her investigation. Which of the following best explains why

the other scientists do this?

There are many different fields of science, each with its own methods of investigation. In which field of science would a field study of volcanoes or other landforms most likely be conducted?

Scientists often replicate experiments to verify the findings. Winch of the following is an example of replication?

Destiny conducted an experiment to test which of four types of batteries lasts longest in a flashlight. She used four identical flashlights and placed a different type of new battery in each flashlight. She turned the flashlights on at the same time, and she recorded the time when each flashlight stopped giving off light. Destiny's data are shown.

What is the independent variable in this experiment?

A scientist conducted an investigation to determine the relationship between algae growth and available light at increasing ocean depths. The scientist lowered a light meter into the ocean and recorded the amount of light at different depths. The scientist also collected a water sample at each depth to count the number of algae present. The table below shows the results.

Based on the information in the table, which of the following statements best describes the relationship between light and the density of the algae population?

Christian conducts an experiment to test the hypothesis that adding sugar to water increases its boiling point. Christian conducts several trials of the experiment. What does conducting the trials allow Christian to do?

Hannah conducted an experiment to determine the temperature at which an unknown substance freezes. She conducted multiple trials of her experiment. Then Angel followed Hannah's procedure to verify her results. Which of the following statements best compares what Hannah and Angel did?

Mr. Benjamin asked his class to form four groups. He provided the groups with identical balances, rulers, and metal blocks. He asked each group to use the tools to determine the mass, volume, and density of its block. The table below shows each group's data.

Mr. Benjamin informed the class that the actual density of each metal block was 3.21 g/cm³. Which of the following is most likely responsible for differences in the data?

A scientist is investigating two unknown organisms. She plans to use the characteristics of the organisms to classify them. She has observed each organism and samples of its cells and has recorded her observations. The table lists some of her observations.

An experiment is only one of several different kinds of investigations that scientists conduct. Which of the following statements best describes why the scientist's investigation is NOT an experiment?

Different methods are used in conducting investigations in different fields of science. Which of the following is a scientist in the field of biology most likely to do?

A scientist measured the weight of a steel ball on an ocean beach and again on a mountaintop and compared the measurements. The scientist found that the ball weighed slightly more on the beach than on the top of the mountain. Based on this information, which of the following is the most logical hypothesis for the scientist to state?

Keesha 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 (cm) from a light source. Keesha counted the bubbles released from the plant every minute for five minutes (min). She repeated the process two more times. First, she moved the light to 20 cm from the beaker, and then she moved the light to 30 cm from the beaker. Keesha’s setup and data are shown below.

What is the outcome variable (dependent variable) in this experiment?

The statements in the chart were taken from the procedures of four different investigations. The statement from which investigation is an example of repetition?

Grace wants to find out how many kinds of organisms live in tide pools on a certain rocky shore. Which of the following would be the best investigation for Grace to conduct?

Christopher states the hypothesis that a mouse's body temperature decreases as the air temperature around the mouse decreases. He wants to design an experiment to test his hypothesis. What should the dependent variable be in

this experiment?

Litmus paper is often used as an indicator to find the pH of a substance and determine if the substance is an acid or base. The procedure for an investigation using litmus paper to classify substances is shown below. The steps of the procedure should be performed in a certain order. Which of the following lists these steps in the order in which they should be performed during the investigation?

The following statements were taken from the procedures of four different investigations. The statement from which investigation is an example of repetition?

Different methods are used in conducting investigations in different fields of science. Which of the following is a scientist in the field of physics most likely to do?

At a science conference, a scientist presented the results ol his field study on dinosaur fossils. Other scientists disagreed with the conclusions, and a debate occurred. How might this debate most likely benefit scientific knowledge?

A scientist designs and conducts an experiment to see if a new skin cream heals burns faster than an existing cream. Which of the following should the scientist do next to make sure the investigation and results are valid?

Two recent models of the atom are shown below. The modem model has replaced the Bohr model in current scientific thinking. Which of the following statements explains why the atomic model has changed?

There are many different fields of science, each with its own ways of pursuing scientific knowledge. In which field of science would a laboratory experiment on cell division most likely be conducted?