What is a control group used for in scientific studies?
A. To establish causality by isolating the effect of an independent variable.
B. To establish the effect of a dependent variable on an independent variable.
C. To control the impact of extraneous variables on the dependent variable.
D. To control the impact of extraneous variables on the independent variable.
A control group is used in scientific studies to establish causality by isolating the effect of an independent variable.
The control group serves as a baseline or comparison group that does not receive the treatment or intervention being tested.
 |
By comparing the results of the control group to the experimental group, researchers can determine if any observed changes are due to the independent variable or if they are due to chance or other factors.
Choice B is incorrect because a control group is not used to establish the effect of a dependent variable on an independent variable.
Choice C is incorrect because while a control group can help control for the impact of extraneous variables on the dependent variable, its primary purpose is to isolate the effect of the independent variable.
Choice D is incorrect because a control group is not used to control for the impact of extraneous variables on the independent variable.
Therefore, the Correct Answer is A.
More Questions on TEAS 7 Science
-
Q #1: What is the hallmark of adaptive immunity?
A. Rapid recruitment of immune cells to sites of infection and inflammation
B. Antigen-independent defense mechanism
C. Immunologic memory
D. Non-specific host-defense mechanisms .
Answer Explanation
Immunologic memory is the hallmark of adaptive immunity.
Immunologic memory enables the host to mount a more rapid and efficient immune response upon subsequent exposure to the antigen.
Choice A is incorrect because rapid recruitment of immune cells to sites of infection and inflammation is a characteristic of innate immunity.
Choice B is incorrect because antigen-independent defense mechanisms are characteristic of innate immunity.
Choice D is incorrect because non-specific host-defense mechanisms are characteristic of innate immunity.
-
Q #2: A nurse is reviewing the results of a patient’s DNA sequencing test, which was performed to diagnose a genetic disorder. The nurse notices that the patient has a mutation in one of the bases of the DNA. Which of the following is the correct term for this type of mutation?
A. Deletion
B. Insertion
C. Substitution
D. Inversion
Answer Explanation
The correct answer is choice C. Substitution.
A substitution mutation is a type of point mutation where one base in the DNA sequence is replaced by another base.
Choice A is incorrect because a deletion mutation occurs when one or more bases are removed from the DNA sequence.
Choice B is incorrect because an insertion mutation occurs when one or more bases are added to the DNA sequence.
Choice D is incorrect because an inversion mutation occurs when a segment of DNA is reversed within the chromosome.
-
Q #3: Which type of bond is responsible for the unique properties of water and plays a crucial role in the structure of DNA and proteins?
A. Hydrogen bonds.
B. Covalent bonds.
C. Ionic bonds.
D. Van der Waals forces.
Answer Explanation
The correct answer is choice A. Hydrogen bonds.
Hydrogen bonds are responsible for the unique properties of water and play a crucial role in the structure of DNA and proteins.
Hydrogen bonds are weak electrostatic attractions between a hydrogen atom covalently bonded to an electronegative atom and another electronegative atom.
Choice B.
Covalent bonds is incorrect because covalent bonds are strong chemical bonds formed by the sharing of electrons between two atoms.
Choice C.
Ionic bonds is incorrect because ionic bonds are chemical bonds formed by the transfer of electrons from one atom to another, resulting in the formation of ions.
Choice D.
Van der Waals forces is incorrect because Van der Waals forces are weak intermolecular forces that arise from temporary dipoles induced in atoms or molecules.
-
Q #4: Which of the following is true regarding the role of oncogenes in cancer development?
A. Mutations in oncogenes always result in the inhibition of cell division.
B. Oncogenes are only found in human cells and not in any other organism.
C. Genes that regulate cell division are not found in any viruses.
D. Genes that regulate cell division can become oncogenes when mutated.
Answer Explanation
The correct answer is choice D.
Genes that regulate cell division can become oncogenes when mutated.
Oncogenes are mutated genes that can contribute to the development of cancer.
In their non-mutated state, everyone has genes which are referred to as proto- oncogenes.
When proto-oncogenes are mutated or increased in numbers due to DNA damage, the proteins produced by these genes can affect the growth, proliferation, and survival of the cell, and potentially result in the formation of a malignant tumor.
Choice A is incorrect because mutations in oncogenes do not always result in the inhibition of cell division.
Instead, they can contribute to the development of cancer by affecting cell growth.
Choice B is incorrect because oncogenes are not only found in human cells but can be present in other organisms as well.
Choice C is incorrect because genes that regulate cell division can be found in viruses. -
Q #5: A nurse is conducting a research study to compare the effects of two different pain medications on postoperative patients. The nurse randomly assigns the patients to either receive medication A or medication B. Which of the following is the best way to ensure that the study is valid and reliable?
A. Use a large sample size and a standardized procedure for administering the medications.
B. Use a placebo group and a double-blind technique for giving the medications.
C. Use a matched-pairs design and a crossover technique for switching the medications.
D. Use a convenience sample and a pretest-posttest design for measuring the pain levels.
Answer Explanation
The correct answer is choice B.
Using a placebo group and a double-blind technique for giving the medications is the best way to ensure that the study is valid and reliable.
A placebo group helps control for the placebo effect, which can influence the results of a study.
A double-blind technique means that neither the patients nor the researchers know which medication is being given, reducing bias.
Choice A is not the best answer because while a large sample size and standardized procedure can increase reliability, they do not address validity.
Choice C is not the best answer because a matched-pairs design and crossover technique are useful for reducing variability but do not address validity.
Choice D is not the best answer because a convenience sample may not be representative and a pretest-posttest design does not control for extraneous variables.
-
Q #6: Which process involves the fusion of male and female gametes resulting in the formation of a zygote?
A. Oogenesis.
B. Fertilization.
C. Meiosis.
D. Mitosis.
Answer Explanation
Fertilization.
Fertilization is the process by which male and female gametes fuse to form a zygote.
Oogenesis (choice A) is the process by which female gametes, or eggs, are produced.
Meiosis (choice C) is a type of cell division that results in the formation of gametes.
Mitosis (choice D) is a type of cell division that results in the formation of two identical daughter cells.
-
Q #7: How do neurons communicate with each other?
A. Through electrical signals only
B. Through chemical signals only
C. Through electrical and chemical signals
D. Through mechanical signals only.
Answer Explanation
Neurons communicate with each other through both electrical and chemical signals.
The electrical signal, or action potential, runs from the cell body area to the axon terminals, through a thin fiber called axon.
Neurons also communicate with one another at junctions called synapses.
At a synapse, one neuron sends a message to a target neuron—another cell.
Most synapses are chemical; these synapses communicate using chemical messengers.
Choice A is incorrect because neurons communicate not only through electrical signals but also through chemical signals.
Choice B is incorrect because neurons communicate not only through chemical signals but also through electrical signals.
Choice D is incorrect because neurons do not communicate through mechanical signals.
-
Q #8: What is the organelle that encapsulates the contents of the cell and plays a vital role in regulating the movement of substances in and out of the cell?.
A. Ribosome
B. Nucleus
C. Mitochondria
D. Plasma membrane.
Answer Explanation
The plasma membrane is the organelle that encapsulates the contents of the cell and plays a vital role in regulating the movement of substances in and out of the cell.
It is a selectively permeable barrier that separates the internal environment of the cell from the external environment.
Choice A is incorrect because ribosomes are organelles involved in protein synthesis, not in regulating the movement of substances in and out of the cell.
Choice B is incorrect because the nucleus is an organelle that contains the cell’s genetic material, not in regulating the movement of substances in and out of the cell.
Choice C is incorrect because mitochondria are organelles involved in energy production, not in regulating the movement of substances in and out of the cell.
-
Q #9: A nurse is caring for a patient who has been declared brain dead and is awaiting organ donation. Which of the following interventions is most important to preserve the viability of the organs?
A. Administering antibiotics to prevent infection.
B. Maintaining normal body temperature and blood pressure.
C. Providing emotional support to the family members.
D. Applying eye drops and ointment to prevent corneal drying.
Answer Explanation
The correct answer is choice B.
Maintaining normal body temperature and blood pressure.
Early identification and management of potential organ donors must take into consideration specific pathophysiologic changes for medical optimization 1.
The VIPPS (ventilation, infusion and pumping, pharmacological treatment, and specificities) strategy is a mnemonic method that brings together key aspects of the restoration of oxygen delivery to tissues during hemodynamic instability plus organ optimization strategies.
Choice A is incorrect because administering antibiotics to prevent infection is not the most important intervention to preserve organ viability.
Choice C is incorrect because providing emotional support to family members, while important, is not an intervention that directly affects organ viability.
Choice D is incorrect because applying eye drops and ointment to prevent corneal drying is not the most important intervention to preserve organ viability.
-
Q #10: Which of the following organelles is responsible for modifying, sorting and packaging proteins and lipids?
A. Golgi apparatus
B. Mitochondria
C. Ribosomes
D. Endoplasmic reticulum
Answer Explanation
The correct answer is choice A. Golgi apparatus.
The Golgi apparatus is a membrane-bound organelle that is responsible for transporting, modifying, and packaging proteins and lipids into vesicles for delivery to targeted destinations.
Choice B is incorrect because mitochondria are responsible for energy production.
Choice C is incorrect because ribosomes are responsible for protein production.
Choice D is incorrect because the endoplasmic reticulum is responsible for lipid production and protein production, but not for modifying, sorting and packaging proteins and lipids.
