A biology teacher wants a routine in which teacher and students build the meaning of an article on enzymes through shared dialogue. Which method, with its strategies, fits?Wikipedia, Reciprocal teaching. Written to the ILTS Science: Biology (239) test framework, objective 0003
A chapter on membranes uses the words diffusion, osmosis and solute. By the research summarized in Put Reading First, when does teaching such specific words help most?Put Reading First, third edition (National Institute for Literacy). Written to the ILTS Science: Biology (239) test framework, objective 0003
A sample has an accepted mass of 15.00 g. Four readings on one balance are 12.41 g, 12.40 g, 12.42 g and 12.41 g. How should the readings be described?Wikipedia, Accuracy and precision. Written to the ILTS Science: Biology (239) test framework, objective 0001
A thermostat switches a heater off once a room warms past its set point. Which idea about stability and change does this model?Wikipedia, Negative feedback. Written to the ILTS Science: Biology (239) test framework, objective 0002
Show all 44 questions (40 more)
Science process skills, continued
A three-column chart is filled in before and after a reading on photosynthesis. Its first column holds what students knew beforehand. What do the letters heading the three columns stand for?Wikipedia, KWL table. Written to the ILTS Science: Biology (239) test framework, objective 0003
In a lab report a student writes, "My experiment proved my hypothesis." What should the teacher point out about the wording?Wikipedia, Scientific theory. Written to the ILTS Science: Biology (239) test framework, objective 0001
Students give fertilizer to half of a set of identical seedlings and none to the other half. What do the unfertilized seedlings provide?Wikipedia, Scientific control. Written to the ILTS Science: Biology (239) test framework, objective 0001
Students raise radish seedlings in soils of pH 5, 6, 7 and 8 and record each plant's height after two weeks. Which is the independent variable?Wikipedia, Dependent and independent variables. Written to the ILTS Science: Biology (239) test framework, objective 0001
To model why cells stay small, a teacher soaks agar cubes of 1 cm, 2 cm and 3 cm in dye. Which cube has the largest surface-area-to-volume ratio?Wikipedia, Surface-area-to-volume ratio. Written to the ILTS Science: Biology (239) test framework, objective 0002
Vinegar and baking soda with a total mass of 10 g react inside a flask sealed so that no matter enters or leaves. What is the mass of the contents afterward?Wikipedia, Conservation of mass. Written to the ILTS Science: Biology (239) test framework, objective 0002
Disciplinary core ideas 16
A pea plant shows a recessive trait, wrinkled seeds. What must be true of the two alleles it inherited for that gene?NHGRI Talking Glossary, Recessive Traits and Alleles. Written to the ILTS Science: Biology (239) test framework, objective 0006
A pendulum bob swings inside a sealed jar from which the air has been pumped, so that friction can be ignored. As the bob falls from its highest point, what happens to the energy of the system?Wikipedia, Conservation of energy. Written to the ILTS Science: Biology (239) test framework, objective 0005
A power plant upwind of a forest lake burns high-sulfur coal. Emissions of which pollutants lead to acid rain?U.S. Environmental Protection Agency, What is Acid Rain?. Written to the ILTS Science: Biology (239) test framework, objective 0008
A root-tip cell of an onion holds 16 chromosomes. After one division by mitosis, how do the daughter nuclei compare?Wikipedia, Mitosis. Written to the ILTS Science: Biology (239) test framework, objective 0006
A sound wave moves through air at a fixed speed. If the frequency of the wave is doubled, what happens to its wavelength?Wikipedia, Wavelength. Written to the ILTS Science: Biology (239) test framework, objective 0005
A student says summer comes when Earth is nearest the Sun. Which explanation of the seasons should replace that idea?Wikipedia, Season. Written to the ILTS Science: Biology (239) test framework, objective 0007
Carbon has four valence electrons; each hydrogen atom has one. Why do valence electrons let a student predict how an element will react?Wikipedia, Valence electron. Written to the ILTS Science: Biology (239) test framework, objective 0004
For more than 200 years the ocean has taken up carbon dioxide released by burning fossil fuels. What has this uptake done to seawater?NOAA National Ocean Service, What is Ocean Acidification?. Written to the ILTS Science: Biology (239) test framework, objective 0008
Grains of sand settle on a river delta, are buried, and over time are cemented together into sandstone. Which class of rock has formed?Wikipedia, Sedimentary rock. Written to the ILTS Science: Biology (239) test framework, objective 0007
In a molecule of water, each hydrogen atom shares a pair of electrons with the oxygen atom. What kind of bond holds each hydrogen to the oxygen?Wikipedia, Covalent bond. Written to the ILTS Science: Biology (239) test framework, objective 0004
In a simple circuit, the voltage across an ohmic resistor is doubled. What happens to the current through the resistor?Wikipedia, Ohm's law. Written to the ILTS Science: Biology (239) test framework, objective 0005
The lining of the airway is epithelium. The lung is built of several such groupings, and the lungs and airways work together in breathing. Which terms name epithelium, lung and the breathing apparatus, in that order?Wikipedia, Biological organisation. Written to the ILTS Science: Biology (239) test framework, objective 0006
The Mid-Atlantic Ridge widens by 10 to 40 millimeters a year as new ocean basin forms along it. How are the two plates at the ridge moving?Wikipedia, Plate tectonics. Written to the ILTS Science: Biology (239) test framework, objective 0007
Sodium and potassium stand in the same group of the periodic table. What does that position let a student predict about them?Wikipedia, Periodic table. Written to the ILTS Science: Biology (239) test framework, objective 0004
Under a microscope a student finds a one-celled organism with no distinct nucleus and no membrane-bound organelles. How is it classed?Wikipedia, Prokaryote. Written to the ILTS Science: Biology (239) test framework, objective 0006
Which statement describes the greenhouse effect?NASA Science, What is the greenhouse effect?. Written to the ILTS Science: Biology (239) test framework, objective 0008
Biochemistry, cells and energetics 5
A cell's chromosomes must be copied before mitosis can separate them. During which part of the cell cycle does this DNA replication take place?Wikipedia, Mitosis. Written to the ILTS Science: Biology (239) test framework, objective 0010
How does an enzyme speed up a reaction in a cell?Wikipedia, Enzyme. Written to the ILTS Science: Biology (239) test framework, objective 0009
In the theory of symbiogenesis, what gave rise to the mitochondria of eukaryotic cells?Wikipedia, Symbiogenesis. Written to the ILTS Science: Biology (239) test framework, objective 0010
Lettuce leaves left in a salty dressing go limp within the hour. In terms of tonicity, what happened to their cells?Wikipedia, Tonicity, Hypertonic solution. Written to the ILTS Science: Biology (239) test framework, objective 0010
Muscle cells oxidize glucose in cellular respiration. What does the process produce that the cell can spend directly on its work?Wikipedia, Cellular respiration. Written to the ILTS Science: Biology (239) test framework, objective 0009
Molecular biology, genetics and evolution 8
A forensic laboratory has only a trace of DNA and needs billions of copies of one segment for study. Which technique does it use?NHGRI Talking Glossary, Polymerase Chain Reaction (PCR). Written to the ILTS Science: Biology (239) test framework, objective 0011
A mutation deletes two nucleotides from the middle of a gene. What is the effect when the gene is read to make a protein?NHGRI Talking Glossary, Frameshift Mutation. Written to the ILTS Science: Biology (239) test framework, objective 0011
A woman carries one copy of a recessive allele on an X chromosome, and her partner does not have it. Why is every son who inherits her allele affected?Wikipedia, Sex linkage. Written to the ILTS Science: Biology (239) test framework, objective 0012
Before a gene can be transcribed, RNA polymerase and transcription factors must bind to the DNA. Where do they bind?NHGRI Talking Glossary, Promoter. Written to the ILTS Science: Biology (239) test framework, objective 0011
In a lizard population, animals of medium body size leave the most offspring, and the smallest and largest leave few. Which mode of natural selection is acting?Wikipedia, Stabilizing selection. Written to the ILTS Science: Biology (239) test framework, objective 0013
In a wildflower population in Hardy-Weinberg equilibrium, 9% of plants have white flowers, the recessive phenotype. What share of the plants is expected to be heterozygous?Wikipedia, Hardy-Weinberg principle. Written to the ILTS Science: Biology (239) test framework, objective 0013
In guinea pigs, black coat (B) is dominant to brown and short hair (S) to long, and the two genes lie on different chromosomes. Two BbSs animals mate. What share of the young is expected to be black with short hair?Wikipedia, Dihybrid cross. Written to the ILTS Science: Biology (239) test framework, objective 0012
Sickle cell disease is inherited as an autosomal recessive trait. Two parents are carriers and neither has the disease. About what share of their children is expected to have it?NHGRI Talking Glossary, Autosomal Recessive Disorder. Written to the ILTS Science: Biology (239) test framework, objective 0012
Ecology and the unity and diversity of life 5
A student draws blood sugar control as a feedback loop. In the loop, which action of insulin lowers the glucose level?Wikipedia, Insulin. Written to the ILTS Science: Biology (239) test framework, objective 0015
In the scientific name Quercus alba, the white oak, what does the first word identify?Wikipedia, Binomial nomenclature. Written to the ILTS Science: Biology (239) test framework, objective 0015
The producers in a prairie plot convert 10,000 kJ of energy into biomass in a year. About how much becomes biomass in the primary consumers that feed on them?Wikipedia, Trophic level. Written to the ILTS Science: Biology (239) test framework, objective 0014
The red fox, Vulpes vulpes, and the Arctic fox, Vulpes lagopus, are placed in one genus. Which other rank must the two species also share?Wikipedia, Taxonomic rank. Written to the ILTS Science: Biology (239) test framework, objective 0015
Two species of one-celled grazers are raised together on a single limited food supply, and one species dies out in every trial. Which principle does the result show?Wikipedia, Competitive exclusion principle. Written to the ILTS Science: Biology (239) test framework, objective 0014
How this list was compiled: Our own questions, written to the test design and framework of field 239, Science: Biology, in the study guide on the Illinois Licensure Testing System website (https://www.il.nesinc.com/Content/STUDYGUIDE/IL_SG_OBJ_239.htm, copyright 2020 Pearson Education, Inc.; test page https://www.il.nesinc.com/TestView.aspx?f=HTML_FRAG/IL239_TestPage.html, read 2026-10-12): 100 multiple-choice questions in 3 hours 15 minutes, passing score 240; Science Process Skills (objectives 0001 to 0003, 23%), Disciplinary Core Ideas (0004 to 0008, 37%), Biochemistry, Cells, and Energetics (0009 and 0010, 11%), Molecular Biology, Genetics, and Evolution (0011 to 0013, 18%) and Ecology and the Unity and Diversity of Life (0014 and 0015, 11%). The bank holds 44: 10, 16, 5, 8 and 5. Every fact was read on the public page named under its question: the Talking Glossary of the National Human Genome Research Institute, the U.S. Environmental Protection Agency, NOAA's National Ocean Service, NASA Science, Put Reading First and the named Wikipedia articles. Licence: Questions, choices and explanations are original work of this site.
How it works
This free ILTS Biology practice test holds 44 questions of our own on Science: Biology, field 239. It is unofficial and not affiliated with the Illinois State Board of Education or Pearson.
Read the full guide
ILTS Science: Biology (239): the five subareas
By the framework on the ILTS site, read October 12, 2026: Science Process Skills 23%, Disciplinary Core Ideas 37%, Biochemistry, Cells, and Energetics 11%, Molecular Biology, Genetics, and Evolution 18%, and Ecology and the Unity and Diversity of Life 11%. This bank holds 10, 16, 5, 8 and 5. Exam mode draws 40 for 78 minutes, the real pace.
More than a third is not biology alone
Disciplinary Core Ideas takes in chemistry, physics, Earth and space science and environmental science beside biology, so this bank asks about bonds, energy, waves, plate boundaries and acid rain. Objective 0003 is reading in the science classroom.
The test page lists two reference materials given on screen: a scientific calculator and a periodic table.
Questions and answers
Is this ILTS Biology practice test free?
Yes: no fee and no sign-up. The 44 questions were written for this page, one objective of the Illinois framework at a time, and every explanation names the public page where its fact can be checked. The official sample questions were not used.
Is this an ILTS Biology 105 practice test?
The ILTS test list, read October 12, 2026, gives Science: Biology the code 239 and shows no test numbered 105. These questions follow the framework of field 239, the test given today.
How many questions are on the ILTS Biology test?
The test page gives 100 multiple-choice questions on a computer, with 3 hours 15 minutes of testing time in an appointment of 3 hours 30 minutes. The framework counts 80 of the questions as scorable.
What is the passing score for ILTS Biology?
The test page gives 240, read October 12, 2026. How many correct answers earn 240 is not published, so the result here is a plain count with no pass or fail.