Quarter 1 Review

Nina wanted to know whether different brands of soda hold different levels of carbonation. She observed people opening sodas over several weeks. Nina concluded that some brands hold more carbonation because they were more likely to foam when opened. Which of the following best describes the evidence Nina gathered through her observations?

• Nina’s observations are sufficient to form a scientific conclusion.

• Nina could use her data to form a hypothesis and test it with an experiment.

• The data from Nina’s observations led her to an incorrect scientific conclusion.

• Nina should disregard her observations because they did not result from a controlled experiment.

A group of students want to investigate the effects of plant moisture on the growth of caterpillars. The students fill three identical boxes with an equal number of a kind of leaf that caterpillars eat. The students keep the leaves in the first box dry, spray the leaves in the second box with two sprays of water, and spray the leaves in the third box with four sprays of water. The students then add four caterpillars to each box. Every day the length of each caterpillar is measured and recorded, and the results are averaged. What is the test variable (independent variable) in this experiment?

• The number of leaves put in each box

• The amount of water put on the leaves

• The number of caterpillars in each box

• The change in length of the caterpillars

Allison and Heather are going to conduct an experiment to see whether salt affects the growth of plants. They assemble five groups of identical plants and give the plants in each group water with a different salt concentration. What is the outcome variable (dependent variable) for their experiment?

• Salt concentration in plant tissue

• Salt concentration in plant water

• Amount of water absorbed by plants

• Average mass of plants in each group

Jules wanted to know whether the eating behavior of goldfish is affected by music. He set up a fish tank. Every day, Jules played music for the fish and measured how much the fish ate.

What is Jules missing from this experiment?

• A control group

• A measurable result

• Different types of fish

• An outcome variable (dependent variable)

Scientists have studied glaciers in Greenland as evidence of global warming. One team of scientists predicts that glaciers are melting at an accelerated rate. The scientists collect the same types of data on the same glaciers on the same dates each year for ten years. The scientists conclude that the glaciers have decreased in mass and increased their velocity toward the sea each successive year. Which of the following statements best evaluates the process that the scientists used?

• The process is a flawed experiment because the variables are not controlled.

• The process is a valid experiment because there is an independent variable and a test variable.

• The process is a flawed investigation because the investigators did not begin by forming a hypothesis.

• The process is a valid investigation because scientists used systematic methods for collecting and analyzing information.

Jose performs an experiment to determine how much sugar can be dissolved in 250 milliliters (mL) of water at 25oC. He adds 50 grams (g) of sugar at a time to the water while stirring and observes the solution. After adding sugar the eleventh time (550 g), he notes that undissolved sugar has settled to the bottom of the container. He stops adding sugar and ends his experiment. In his lab write-up he concludes that the solubility of sugar in water at 25oC is 500 g per 250 mL. Is his conclusion defensible, and why or why not?

• No, because he did not add sugar enough times.

• Yes, because when he added more than 500 g it did not all dissolve.

• No, because he does not know if any of the final portion of sugar dissolved.

• Yes, because when he added the tenth portion (500 g) all of it dissolved.

The graph below shows which wavelengths, in nanometers (nm), and corresponding colors of light are absorbed by the plant molecule chlorophyll a. Chlorophyll a is one of the molecules that plants use for photosynthesis.

Which of the following would be an accurate analysis of the information shown?

• The least effective color of light for photosynthesis appears to be green.

• The lease effective colors of light for photosynthesis appear to be orange and red.

• The most effective wavelengths of light for photosynthesis are between 450 and 550 nm.

• The lease effective wavelengths of light for photosynthesis are between 600 and 700 nm.

Denise and David are testing how plants respond to fertilizer. They use three plants for the experiment. The first is given a cup of Fast Grow fertilizer with no water. The second is given a teaspoon of SunLight fertilizer with a cup of water. The third plant is given no fertilizer with a cup of water.

Denise and David will not be able to draw a valid conclusion from their result. Which of the following statements explains why?

• There are not enough different types of plants.

• There is no test variable (independent variable).

• Results of the experiment need to be presented in a graph.

• More than one test variable (independent variable) has been changed in the experiment.

Organisms can pass on genetic information through asexual or sexual reproduction. Which of the following statements best describes how asexual reproduction differs sexual reproduction?

• During asexual reproduction, offspring receive DNA from several parents rather than just one parent.

• During asexual reproduction, offspring receive DNA as individual atoms rather than genes.

• During asexual reproduction, offspring receive DNA from one parent rather than two.

• During asexual reproduction, a parent cell divides by meiosis rather than mitosis.

In a species of rabbit, F is the dominant allele for brown fur, and f is the recessive allele for black fur. Two rabbits have four offspring. Three have brown fur, and one has black fur. Which of the following could describe the genotypes of the parents?

• Both parents are heterozygous, with one dominant allele and one recessive allele.

• One parent is homozygous and has brown fur, while the other is homozygous and has black fur.

• One parent is homozygous with dominant alleles, and the other is heterozygous with two recessive alleles.

• Both parents are homozygous, and one of the parents has dominant alleles while other has recessive alleles.