NLN NEX Science Practice Test 2026 [Timed] 55 Questions

1) The retina transmits nerve impulses to the brain via the

2) The organ that works to detoxify the blood and to produce bile is the

3) A secondary defense for the body against pathogens is

4) The larynx is covered by the ______ so that food does not enter the trachea.

5) During breathing, the air pressure in the lungs changes as a result of

6) The iris and retina are parts of the

7) Which of the following is not a type of muscle?

8) Avogadro’s number is the number of

9) Ligaments hold

10) Which substance shows a decrease in solubility in water with an increase in temperature?

11) Which locations in the digestive system are sites of chemical digestion?

I. Mouth
II. Stomach
III. Small Intestine

12) The ribs are ______ to the lungs in the human body.

13) Animals like snails and clams contained within a hard shell differ from humans because they lack

14) The brain and the spinal cord make up the

15) The small intestine contains a large quantity of villi that help

16) The growth and development of bone is assisted by the use of vitamin D because vitamin D can

17) Which reproductive organ belongs to a different system from the other three?

18) As water is evaporated from a solution, the concentration of the solute in the solution will

19) What is the percent of oxygen in H₂O?

20) Given a sample of C₆H₁₂O₆(aq), which of the following is true?

21) Yeast is used to make bread rise because

22) Which of the following statements is true?

23) The compound CH₂=CH–CH₂–CH₂–CH₃ is an example of

24) The heart is composed of which type of tissue?

25) As shown in the heart diagram on the previous page, separating the left and right sides of the heart is the

26) Salt is added to a sample of water. Which of the following is true?

27) The word renal refers to the

28) A cell is in a solution in which the concentration of solutes is higher inside the cell than outside the cell. The cells will likely

29) Which statement does not have the same truth value as the others?

30) Which muscle pushes food through the digestive system?

31) The name of the compound CH₃–CH₂–CH₂–CH₃ is most likely

32) Given one mole of O₂ gas at STP, what is the mass of this sample?

33) Which statement about white blood cells is true?

34) Which of the following glands is not paired up with a hormone that it produces?

35) Which vitamin is essential for calcium absorption and bone health?

36) Which is the cellular organelle used for digestion to recycle materials?

37) The arrow in the following diagram represents the wave’s

38) The function of the diaphragm in a human being is

39) If 58.5 g of NaCl (1 mole of NaCl) are dissolved in enough water to make 0.500 L of solution, what is the molarity of this solution?

40) A person gets hit in the face with a puck while playing ice hockey and fractures a bone. Which bone is a most likely candidate for this fracture?

41) In classifying all living things on Earth, which of the following groups would sort all life into two groups?

42) Which of the following causes and effects would occur last in a shallow forest pond that is not fed with a source of freshwater replacement like a larger river?

43) Quantities having both magnitude and direction are

44) Organic compounds are the basis for life as we know it because

45) Which of the following are considered normal values for the measurements of a person’s pulse and blood pressure?

46) Synapses are the gaps between

47) Exactly 2.0 moles of an element weigh 8.0 grams. Which of the following is true?

48) What is the temperature as shown on this thermometer?

49) Which of the following structures is unique to eukaryotic cells?

50) The process by which oxygen travels from the air into your lungs and then into your blood is called

51) The heart and veins have valves to ensure that

52) Which of the following is a way in which mitosis differs from meiosis?

53) According to the table above, a patient with an elevated PaCO₂ count needs

54) Which of the following are functions of the urinary system?

I. Synthesizing calcitriol and secreting erythropoietin
II. Regulating the concentrations of sodium, potassium, chloride, calcium, and other ions
III. Reabsorbing or secreting hydrogen ions and bicarbonate
IV. Detecting reductions in blood volume and pressure

55) Given patients whose age, weight, sex, and temperament are nearly identical, what should the normal values of blood pressure and pulse be during routine examinations and measurements by a physician?