A class soaked 50 radish seeds per group in salt solutions of different strengths and counted how many germinated. Use the table. Which conclusion is supported by the data?

A student counted the gas bubbles released each minute by a sprig of Elodea placed at different distances from a lamp. Use the graph. About how many bubbles per minute were produced at 30 cm?

A class tests whether a fertilizer changes how fast radish seedlings grow. Every group gets the same volume of water, the same light and the same temperature; only the amount of fertilizer differs. Why are those other conditions held the same?

Researchers test whether a plant extract slows the growth of a mold. Ten dishes of mold receive the extract dissolved in a solvent. Ten identical dishes receive the solvent alone. What is the role of the dishes that receive only the solvent?

In an investigation of a plant growth hormone, each treatment is applied to 20 plants rather than to a single plant. What does using 20 plants per treatment do for the investigation?

A student needs to measure out 25 mL of a nutrient solution as accurately as possible for a lab procedure. Which piece of equipment should the student use?

Use the diagram of a plant cell. Which numbered structure captures light energy and uses it to build sugar?

A student measured the rate of an enzyme-controlled reaction in buffers of different pH. Use the graph. At which pH did this enzyme work fastest?

Use the cycle diagram of a dividing cell. Which phase of mitosis is shown at step 3?

A red blood cell is placed in a beaker of distilled water and soon bursts. What caused the cell to burst?

Root hair cells take in mineral ions from soil water in which the concentration of those ions is lower than the concentration already inside the cell. Which process must the root cells use?

Which summary correctly states the reactants and products of photosynthesis?

Heart muscle cells contain far more mitochondria than the cells lining the inside of the cheek. What does this difference suggest about heart muscle cells?

Plant cells carry out cellular respiration as well as photosynthesis.

Which organelle receives proteins, modifies and packages them, and ships them in vesicles to the cell membrane?

Which feature is present in a eukaryotic cell but absent from a prokaryotic cell?

In guinea pigs, black fur (B) is dominant to white fur (b). Use the Punnett square for the cross shown. What percentage of the offspring are predicted to have white fur?

Use the pedigree. Shaded symbols mark individuals who show the trait. Neither parent in generation I shows it, but one of their sons does. What does this pattern indicate about the allele for the trait?

One strand of a DNA molecule has the base sequence TACGGA. What is the base sequence of the strand paired with it?

A messenger RNA molecule leaves the nucleus of a cell. Where is the protein it codes for actually assembled?

Which outcome describes meiosis but not mitosis?

A mutation changes one base in a gene inside a skin cell of an adult. Will that mutation be passed to the person's children?

In one population of rabbits, the coat color produced by a recessive allele is far more common than the coat color produced by the dominant allele. What does this show?

In an individual that is heterozygous for a trait, the recessive allele is absent from the cells.

Use the cladogram. Which two organisms share the most recent common ancestor?

An organism is multicellular, cannot make its own food, has cell walls containing chitin, and absorbs nutrients from the dead log it grows on. In which kingdom is it classified?

A single-celled organism has no nucleus, reproduces by binary fission, and has a cell wall that contains peptidoglycan. In which kingdom does it belong?

The gray wolf is named Canis lupus and the coyote is named Canis latrans. What does the shared first word of the two names tell a biologist?

Which of these is the correctly written scientific name of the American black bear?

Modern classification places all living things into three domains. Which list names them?

Euglena, amoebas and kelp are all placed in the kingdom Protista. What do these organisms have in common that puts them there?

A student is given an unfamiliar insect and a dichotomous key for the insects of the region. What does the key present at each step?

A hospital recorded the percentage of one bacterial infection that resisted a particular antibiotic over 30 years. Use the graph. Which explanation best accounts for the change?

The forelimbs of a human, a bat and a whale contain the same arrangement of bones but are used for handling objects, flying and swimming. What is the best explanation for this similarity?

Which condition must already exist in a population before natural selection can change it over generations?

A geologist studies undisturbed sedimentary rock layers containing fossils. How do the fossils in the deeper layers compare with those in the layers above them?

Use the food web. A disease sharply reduces the mouse population. What is the most likely immediate effect on the snake population?

Why do food chains rarely contain more than four or five trophic levels?

A tick attaches to a deer, feeds on its blood over several days, and leaves the deer weakened. Which relationship does this describe?

Deer released on an island increase rapidly for several years, then level off near 250 animals and stay near that number. What best explains the leveling off?