Free TEAS Science Questions Practice Test (2026 Update)

Explanation: In acid-base neutralization reactions, water is always produced when hydrogen ions (H+) from the acid combine with hydroxide ions (OH-) from the base. A salt is also typically formed.

Explanation: The number of electrons in the outermost shell (valence electrons) determines an element's chemical properties and how it will bond with other elements.

Explanation: Photosynthesis is the process by which plants convert light energy (usually from the sun) into chemical energy (glucose) using carbon dioxide and water, releasing oxygen as a byproduct.

Explanation: Ribosomes are the cellular structures responsible for protein synthesis. They read messenger RNA (mRNA) and assemble amino acids into proteins according to the genetic code.

Explanation: Adrenaline (epinephrine), produced by the adrenal glands, triggers the "fight or flight" response by increasing heart rate, blood pressure, and energy availability during stressful situations.

Explanation: The main functional difference is that arteries carry blood away from the heart to body tissues, while veins return blood from body tissues back to the heart.

Explanation: Ball-and-socket joints (like the shoulder and hip) allow movement in multiple directions and provide the greatest range of motion, including rotation.

Explanation: The lymphatic system helps fight infections by filtering pathogens and producing immune cells, and it maintains fluid balance by returning excess tissue fluid to the bloodstream.

Explanation: Gas exchange occurs in the alveoli, where oxygen from inhaled air diffuses into the blood and carbon dioxide from the blood diffuses into the air to be exhaled.

Explanation: During cellular respiration, glucose is broken down using oxygen to produce ATP (energy), carbon dioxide, and water. The chemical equation is C6H12O6 + 6O2 → 6CO2 + 6H2O + ATP.

Explanation: A positive correlation means that as one variable increases, the other variable tends to increase as well. However, correlation does not necessarily imply causation.

Explanation: There is a positive correlation between exercise intensity and heart rate. As the body requires more oxygen during intense exercise, the heart beats faster to pump more blood to working muscles.

Explanation: The independent variable is what the researcher manipulates, and the dependent variable is what is measured or observed. Changes in the independent variable may cause changes in the dependent variable.

Explanation: A graduated cylinder is designed for accurate volume measurements. While beakers can measure approximate volumes, graduated cylinders provide more precise measurements.

Explanation: If experimental results don't support the hypothesis, scientists should accept the results and revise their hypothesis. This is a normal part of the scientific process.

Explanation: Quantitative measurements involve numbers and units. "25 grams" provides a specific numerical value with units, while the other options are qualitative descriptions.

Explanation: A control group provides a standard for comparison in an experiment. It helps scientists determine whether changes in the experimental group are due to the variable being tested.

Explanation: A hypothesis is a testable explanation or prediction for an observation. It should be specific, measurable, and able to be supported or refuted through experimentation.

Explanation: The scientific method typically begins with making an observation about a phenomenon in the natural world. This observation leads to questions that can be investigated scientifically.

Explanation: Liquids have a definite volume but take the shape of their container. Solids have both definite volume and shape, while gases have neither definite volume nor shape.

Explanation: When an acid and base react in a neutralization reaction, they form a salt and water. The hydrogen ions from the acid combine with hydroxide ions from the base to form water.

Explanation: Acids are characterized by their ability to donate hydrogen ions (H+) in solution. They have a pH less than 7, taste sour, and turn blue litmus paper red.

Explanation: A neutral solution has a pH of 7. The pH scale ranges from 0-14, with 7 being neutral, below 7 being acidic, and above 7 being basic (alkaline).

Explanation: During a chemical reaction, bonds between atoms are broken and/or formed, rearranging atoms to create new substances. The total number of atoms remains constant.

Explanation: The nucleus of an atom contains protons (positively charged) and neutrons (neutral). Electrons orbit around the nucleus in electron shells.

Explanation: The atomic number is the number of protons in an atom's nucleus. This number defines the element and determines its position on the periodic table.

Explanation: Many bacteria play a crucial role in the nitrogen cycle by fixing atmospheric nitrogen into forms that plants can use, such as ammonia and nitrates.

Explanation: Carbohydrates, particularly glucose, are the primary source of energy for cells. They are broken down during cellular respiration to produce ATP.

Explanation: DNA is composed of nucleotides, each containing a phosphate group, a five-carbon sugar (deoxyribose), and one of four nitrogenous bases (A, T, G, C).

Explanation: According to Mendel's law of dominance, when a dominant allele is paired with a recessive allele, the dominant trait is expressed in the phenotype while the recessive allele is masked.

Explanation: Sexual reproduction involves two parents contributing genetic material (gametes) to produce offspring with genetic variation. This increases genetic diversity in populations.

Explanation: Mitosis is the process by which a single cell divides to produce two identical diploid daughter cells. This is how organisms grow and replace damaged cells.

Explanation: The nucleus contains the cell's DNA (genetic material) and controls cellular activities. It is surrounded by a nuclear membrane and contains the nucleolus.

Explanation: The cell membrane (plasma membrane) is selectively permeable and controls what substances can enter and exit the cell. It maintains the cell's internal environment.

Explanation: Mitochondria are called the "powerhouse of the cell" because they produce ATP (adenosine triphosphate), the main energy currency of cells, through cellular respiration.

Explanation: The skin is the largest organ in the human body by surface area. It covers the entire body and serves multiple functions including protection, temperature regulation, and sensory reception.

Explanation: The cerebellum, located at the back of the brain, is responsible for balance, coordination, and fine motor control. It helps coordinate voluntary movements and maintains posture.

Explanation: Red blood cells (erythrocytes) contain hemoglobin, which binds to oxygen in the lungs and transports it to body tissues. They also carry carbon dioxide back to the lungs for elimination.

Explanation: Arteries carry blood away from the heart to body tissues. They have thick, muscular walls to withstand the high pressure of blood being pumped from the heart.

Explanation: The epidermis is the outermost layer of the skin. It provides protection against the environment and contains no blood vessels, receiving nutrients from the underlying dermis.

Explanation: Gonads is the general term for reproductive organs that produce gametes. In males, the gonads are testes (producing sperm), and in females, they are ovaries (producing eggs).

Explanation: The nephron is the basic functional unit of the kidney. Each kidney contains about one million nephrons, which filter blood and produce urine through filtration, reabsorption, and secretion.

Explanation: The immune system is specifically designed to defend the body against pathogens, infections, and foreign substances. It includes white blood cells, antibodies, and lymphatic organs.

Explanation: Insulin, produced by the pancreas, is the primary hormone that regulates blood glucose levels by promoting glucose uptake by cells and storage as glycogen in the liver.

Explanation: The clavicle is commonly called the collarbone. It connects the shoulder blade (scapula) to the sternum (breastbone) and helps support the shoulder.

Explanation: Cardiac muscle is the specialized muscle tissue found only in the heart. It is involuntary like smooth muscle but has striations like skeletal muscle, and it can contract rhythmically on its own.

Explanation: The small intestine, particularly the duodenum and jejunum, is where most nutrient absorption occurs. Its large surface area due to villi and microvilli maximizes absorption efficiency.

Explanation: The autonomic nervous system controls involuntary functions such as heart rate, breathing, digestion, and blood pressure. It has two main divisions: sympathetic and parasympathetic.

Explanation: During inspiration, the diaphragm contracts and flattens, moving downward. This increases the volume of the thoracic cavity, decreasing air pressure in the lungs and drawing air in.

Explanation: The right atrium receives deoxygenated blood returning from the body through the superior and inferior vena cava. The blood then moves to the right ventricle to be pumped to the lungs for oxygenation.