Which of the following properties does soap, an emulsifier, have that make it useful for washing dirt off one’s hands with water?
A. Soap’s dual polar and nonpolar nature helps bond oil and water
B. Soap’s acidity causes grime to precipitate into the water
C. Soap’s enzymatic action helps to dissolve grime into small particles
D. Soap’s rough texture physically scours grime off surfaces
The correct answer is a. Soap’s dual polar and nonpolar nature helps bond oil and water. Soap is an emulsifier, which means that it has both polar and nonpolar regions. The polar regions of soap molecules are atracted to water, while the nonpolar regions are atracted to oil and grease. This allows soap to bond with both water and oil, helping to remove dirt and grime from surfaces.
B. Soap’s acidity does not cause grime to precipitate into the water.
C. Soap does not have enzymatic action that helps to dissolve grime into small particles.
D. Soap’s texture does not physically scour grime off surfaces.
Therefore, the Correct Answer is A.
More Questions on TEAS 7 Science
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Q #1: Which of the following is a protein present in blood plasma?
A. Monocytes
B. Platelets
C. Fibrinogen
D. Lymphocytes
Answer Explanation
The correct answer is c. Fibrinogen. Fibrinogen is a protein present in blood plasma that plays a key role in blood clotting. When an injury occurs and bleeding begins, fibrinogen is converted into fibrin, which forms a mesh-like structure that helps to trap blood cells and form a clot.
A. Monocytes are a type of white blood cell, not a protein present in blood plasma.
B. Platelets are cell fragments that play a role in blood clotting, but they are not a protein present in blood plasma.
D. Lymphocytes are a type of white blood cell, not a protein present in blood plasma.
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Q #2: Which of the following substances is excreted by sweat glands in response to the breakdown of proteins and the formation of ammonia?
A. Lysozymes
B. Urea
C. Water
D. Sebum
Answer Explanation
Urea is a waste product that is formed when proteins are broken down in the body. It is excreted by the kidneys in urine, but small amounts can also be excreted by sweat glands in sweat.
The other options are not substances that are excreted by sweat glands in response to the breakdown of proteins and the formation of ammonia. Lysozymes are enzymes that break down bacterial cell walls, water is a component of sweat but is not specifically related to protein breakdown, and sebum is an oily substance produced by sebaceous glands to lubricate the skin.
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Q #3: Which of the following is an efferent neuron that is responsible for releasing a neurotransmiter that stimulates a muscle cell to contract?
A. Motor neuron
B. Interneuron
C. Sensory neuron
D. Neuroglia
Answer Explanation
An efferent neuron that is responsible for releasing a neurotransmitter that stimulates a muscle cell to contract is a motor neuron ². Motor neurons carry signals from the brain to the peripheral nervous system in order to initiate an action. The neurotransmitter acetylcholine (ACh) is released by motor neurons at the neuromuscular junction in skeletal muscle, causing the muscle to contract ³.
The other options are incorrect because they do not accurately describe the type of neuron responsible for releasing a neurotransmitter that stimulates a muscle cell to contract. Interneurons are found within the central nervous system and facilitate communication between sensory and motor neurons. Sensory neurons carry information from sensory receptors to the central nervous system. Neuroglia are support cells for neurons and do not transmit nerve impulses.
