Which of the following is an example of a double-blind study?
A. Participants are randomly assigned to a treatment group or a control group
B. Participants and researchers both know which group participants are assigned to
C. Participants do not know which group they are assigned to, but researchers do
D. Both participants and researchers do not know which group participants are assigned to
A double-blind study is a research design in which neither the participants nor the researchers know which group participants are assigned to. This is done to minimize bias and ensure that the results of the study are as objective as possible. In a double-blind study, the treatment and control groups are randomly assigned, and the participants and researchers are unaware of which group each participant is assigned to. Option a) is an example of a randomized controlled trial, which is a common research design, but it is not necessarily double-blind. Option b) is an example of an open-label study, in which both the participants and the researchers know which group each participant is assigned to. Option c) is an example of a single-blind study, in which the participants do not know which group they are assigned to, but the researchers do.
Therefore, the Correct Answer is D.
More Questions on TEAS 7 Science
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Q #1: Which of the following is a chemical property of a substance?
A. Density
B. Melting point
C. Boiling point
D. Reactivity with acid
Answer Explanation
Chemical properties are characteristics of a substance that describe its ability to undergo a chemical change or reaction with another substance.
Reactivity with acid is a chemical property because it describes how a substance will react with an acid to produce a new substance. Density, melting point, and boiling point are physical properties that describe how a substance behaves under certain conditions but do not involve a chemical change or reaction.
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Q #2: What is the role of the epididymis in sperm maturation?
A. The epididymis produces sperm cells.
B. The epididymis stores and protects sperm cells until ejaculation.
C. The epididymis is responsible for the transport of sperm cells from the testes to the urethra.
D. The epididymis provides nourishment to sperm cells.
Answer Explanation
The epididymis is a coiled tube located at the back of each testicle where the sperm mature and are stored until ejaculation. Sperm are produced in the testes and then transported to the epididymis where they undergo maturation and become motile. The epididymis provides a protective environment for the sperm, allowing them to mature and become more resilient to external stressors. During ejaculation, the sperm are transported from the epididymis to the vas deferens and then to the urethra for ejaculation.
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Q #3: Which part of the respiratory system is responsible for regulating breathing rate and depth?
A. Bronchi
B. Alveoli
C. Diaphragm
D. Trachea
Answer Explanation
Diaphragm is responsible for regulating breathing rate and depth. It is a dome-shaped muscle located at the
bottom of the chest cavity that contracts and relaxes to help move air in and out of the lungs.
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Q #4: What is the molecular geometry of a molecule of sulphur dioxide (SO2)?
A. Linear
B. Trigonal planar
C. Bent
D. Tetrahedral
Answer Explanation
The molecular geometry of a molecule of sulphur dioxide (SO2) is bent or V-shaped. This is because of the presence of two lone pairs on the sulfur atom, which cause repulsion and distort the bond angles in the molecule.
SO2 has a central sulfur atom bonded to two oxygen atoms by double bonds. The two double bonds and the two lone pairs of electrons on sulfur result in a trigonal planar arrangement of electron pairs around the sulfur atom. However, the repulsion between the lone pairs causes the two oxygen atoms to be pulled closer together, resulting in a bent or V-shaped molecular geometry.
The bent molecular geometry of SO2 affects its properties, such as its polarity and reactivity. SO2 is a polar molecule due to the asymmetric distribution of electrons, which results in a partial positive charge on the sulfur atom and partial negative charges on the oxygen atoms. This polarity makes SO2 a good solvent and reactant in chemical reactions, as well as a contributor to air pollution and acid rain.
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Q #5: What is the primary pigment responsible for photosynthesis in plants?
A. Chlorophyll a
B. Chlorophyll b
C. Carotenoids
D. Anthocyanins
Answer Explanation
Chlorophyll a is the primary pigment responsible for photosynthesis in plants. It is a green pigment that is essential for capturing light energy from the sun and converting it into chemical energy that can be used by the plant. Chlorophyll a absorbs light most efficiently in the blue and red parts of the spectrum, and reflects green light, giving plants their characteristic green color
Chlorophyll b is another type of chlorophyll that is also involved in photosynthesis, but it is not as abundant as chlorophyll a. Chlorophyll b absorbs light most efficiently in the blue and orange parts of the spectrum and reflects yellow-green light.
Carotenoids are pigments that are present in many plants and are involved in photosynthesis as well as protecting the plant from damage caused by excess light. Carotenoids are responsible for the orange, yellow, and red colors of many fruits and vegetables.
Anthocyanins are pigments that give plants their red, purple, and blue colors. While they are not directly involved in photosynthesis, they play a role in atracting pollinators and protecting the plant from damage caused by UV radiation.
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Q #6: Which of the following is an example of an exothermic reaction?
A. Melting ice
B. Burning wood
C. Cooking an egg
D. Dissolving sugar in water
Answer Explanation
Exothermic reactions are reactions that release energy in the form of heat, light, or sound. Burning wood is an example of an exothermic reaction because it releases heat and light. As the wood reacts with oxygen in the air, it undergoes a combustion reaction that releases energy in the form of heat and light. Melting ice is an endothermic reaction because it requires energy input to melt the solid ice into liquid water. Cooking an egg is a chemical reaction that involves denaturing the proteins in the egg, but it is not necessarily exothermic or endothermic. Dissolving sugar in water is also not an example of an exothermic reaction because it does not release energy in the form of heat, light, or sound.
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Q #7: Which of the following is a type of genetic mutation that involves the insertion or deletion of one or more nucleotides in a DNA sequence?
A. Silent mutation
B. Nonsense mutation
C. Frameshift mutation
D. Missense mutation
Answer Explanation
A frameshift mutation is a type of genetic mutation that involves the insertion or deletion of one or more nucleotides in a DNA sequence. This can cause a shift in the reading frame of the genetic code, resulting in a change in the amino acid sequence of the resulting protein. Frameshift mutations can have significant effects on the function of the protein and can lead to genetic disorders or diseases.
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Q #8: What are the five regions of the vertebral column, starting from the top and moving downwards?
A. Cervical, thoracic, lumbar, sacral, coccygeal
B. Thoracic, cervical, lumbar, sacral, coccygeal
C. Lumbar, thoracic, cervical, coccygeal, sacral
D. Sacral, lumbar, cervical, thoracic, coccygeal
Answer Explanation
The vertebral column, also known as the spine or spinal column, is a series of bones called vertebrae that extend from the skull to the pelvis. It provides support for the body and protects the spinal cord. The five regions of the vertebral column, starting from the top and moving downwards, are:
- Cervical: This region is made up of seven vertebrae and is located in the neck. The first two cervical vertebrae, the atlas and the axis, are specialized to allow for head movement.
- Thoracic: This region is made up of twelve vertebrae and is located in the upper and middle back. The thoracic vertebrae are larger than the cervical vertebrae and articulate with the ribs.
- Lumbar: This region is made up of five vertebrae and is located in the lower back. The lumbar vertebrae are the largest and strongest of the vertebrae.
- Sacral: This region is made up of five fused vertebrae and is located in the pelvis. The sacrum forms the posterior wall of the pelvis and articulates with the hip bones.
- Coccygeal: This region is made up of four fused vertebrae and is located at the base of the vertebral column. The coccyx, or tailbone, provides atachment points for muscles and ligaments.
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Q #9: What is the largest organ in the human body by surface area?
A. Brain
B. Heart
C. Liver
D. Skin
Answer Explanation
The largest organ in the human body by surface area is the skin. It covers the entire external surface of the body and has an average surface area of about 20 square feet in adults.
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Q #10: Which of the following types of RNA carries amino acids to the ribosome during protein synthesis?
A. Messenger RNA
B. Ribosomal RNA
C. Transfer RNA
D. Small nuclear RNA
Answer Explanation
Transfer RNA (tRNA) is a type of RNA molecule that carries amino acids to the ribosome during protein synthesis. Each tRNA molecule has a specific sequence of three nucleotides called an anticodon, which pairs with a complementary codon in the messenger RNA (mRNA) sequence. Each tRNA also carries a specific amino acid that corresponds to the codon it recognizes, allowing the ribosome to link the amino acids together in the correct order to form a protein.
In contrast, messenger RNA (mRNA) carries the genetic information from the DNA to the ribosome, where it serves as a template for protein synthesis. Ribosomal RNA (rRNA) is a component of the ribosome itself, where it helps to catalyze the formation of peptide bonds between amino acids. Small nuclear RNA (snRNA) is involved in splicing of pre-mRNA molecules during post-transcriptional processing.
