Which of these body parts does NOT produce melanin?
A. Hair
B. Nails
C. Skin
D. Iris
While melanin can be found in nails, it is not produced there. Melanin is the pigment that provides color to skin, hair, and eyes. Although the specific coloring of one's skin, hair, and eyes are genetically determined. environmental factors such as sun exposure can increase melanin production in the skin to help protect it from damage.
Therefore, the Correct Answer is B.
More Questions on TEAS 7 Science
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Q #1: Which of these body parts does NOT produce melanin?
A. Hair
B. Nails
C. Skin
D. Iris
Answer Explanation
While melanin can be found in nails, it is not produced there. Melanin is the pigment that provides color to skin, hair, and eyes. Although the specific coloring of one's skin, hair, and eyes are genetically determined. environmental factors such as sun exposure can increase melanin production in the skin to help protect it from damage.
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Q #2: Which of the following molecules exhibits ionic bonding?
A. NaCl
B. CO2
C. C6H12O6
D. H2O
Answer Explanation
Sodium chloride exhibits lonic bonding due to the attraction between Na+ ions and Cl- ions.
Typically, elements on the opposite sides of the periodic table (a metal and a nonmetal) form ionic bonds. Carbon dioxide, water, and glucose exhibit covalent bonding. Typically, elements on the same side of the periodic table (two or more nonmetals) form covalent bonds.
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Q #3: A doctor needs to convince his boss to approve a test for a patient. Which statement below best communicates a scientific argument that justifies the need for the test?
A. The patient looks like he needs this test.
B. The doctor feels that the patient needs this test.
C. The patient's symptoms and health history suggest that this test will enable the correct diagnosis to help the patient.
D. The patient has excellent insurance that will pay for several tests, and the doctor would like to run as many tests as possible.
Answer Explanation
A scientific argument should be based on measurable and observable facts such as the patient's current symptoms and health history. Discussing the patient's appearance or the doctor's feelings does not communicate a scientific argument. While insurance may be a factor in most healthcare systems, the status of the patient's Insurance does not communicate a scientific argument that justifies the need for the test
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Q #4: When animals eat, insulin is released from the pancreas, stimulating glucose uptake by the liver. When glucose levels drop, the pancreas reduces insulin release. This is an example of which mechanism for maintaining homeostasis?
A. Negative feedback
B. Positive feedback
C. Stress response
D. Parasympathetic regulation
Answer Explanation
Maintaining homeostasis means that conditions are kept stable and relatively constant. Negative feedback is a mechanism used to reverse or minimize changes in a system. In this example, negative feedback is used to keep the body's glucose and insulin levels stable. Positive feedback (B) is a mechanism that Increases changes in a system. A stress response (C) describes the body's reaction to threats or pressures. Parasympathetic regulation (D) refers to activities of the nervous system, including slowing the heart rate and boosting Intestinal activity.
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Q #5: Which of the following are formed when the plasma membrane surrounds a particle outside of the cell?
A. Golgi bodies
B. Rough endoplasmic reticulum
C. Secretory vesicles
D. Endocytic vesicles
Answer Explanation
Endocytosis is a process by which cells absorb larger molecules or even tiny organisms, such as bacteria, that would not be able to pass through the plasma membrane. Endocytic vesicles containing molecules from the extracellular environment often undergo further processing once they enter the cell.
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Q #6: What types of reaction is Cu (s) + 2AgNO3(aq) → 2Ag(s) + Cu(NO3)2(aq)?
A. Single replacement
B. Double replacement
C. Synthesis
D. Decomposition
Answer Explanation
This is a single replacement reaction in which copper replaces silver. The copper combines with the nitrate ions, and the silver precipitates out. Single replacement reactions have the general form of
A + BC →
AC + B. Double replacement reactions have the general form of AB + CD→
AD + CB. Synthesis reactions have the general form of A + B →
AB. Decomposition reactions have the general form AB→
A+B. -
Q #7: Which of the heart chambers is the largest?
A. Left atrium
B. Right atrium
C. Left ventricle
D. Right ventricle
Answer Explanation
Of the four heart chambers, the left ventricle is the largest. When it contracts, it pushes blood out to the organs and extremities of the body. The right ventricle pushes blood into the lungs. The atria, on the other hand, receive blood from the outlying parts of the body and transport it into the ventricles.
The basic process works as follows: Oxygen-poor blood fills the right atrium and is pumped into the right ventricle. from which it is pumped into the pulmonary artery and on to the lungs. In the lungs, this blood is oxygenated. The blood then reenters the heart at the left atrium, which, when full, pumps into the left ventricle. When the left ventricle is full, blood is pushed into the aorta and on to the organs and extremities of the body.
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Q #8: Which of the following is NOT provided as a result of the valid research and observations recorded by scientists?
A. A better understanding of the physical world
B. The ability to predict possible outcomes affected by actions
C. The ability to prevent earthquakes and other natural disasters
D. The creation of various substances and technologies that enhance our world
Answer Explanation
Scientists make observations, gather data, and complete research over many years in order to compile knowledge that will provide insight into future disasters, such as earthquakes, storms, and global warming. Although science can be used to predict earthquakes and other natural disasters, there is currently no way of preventing them from occurring.
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Q #9: What is the typical way a solid would turn to a liquid and then to a gas?
A. Vaporizing, then melting
B. Melting, then freezing
C. Vaporizing, then freezing
D. Melting, then vaporizing
Answer Explanation
A solid turns into a liquid by melting, and a liquid turns into gas by vaporization.
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Q #10: Which structure of the nervous system carries action potential in the direction of a synapse?
A. Cell body
B. Axon
C. Neuron
D. Myelin
Answer Explanation
Axons carry action potential in the direction of synapses. Axons are the long, fiber-like structures that carry information from neurons. Electrical impulses travel along the body of the axons, some of which are up to a foot long.
A neuron is a type of cell that is responsible for sending information throughout the body. There are several types of neurons, including muscle neurons, which respond to instructions for movement; sensory neurons, which transmit information about the external world; and interneurons, which relay messages between neurons. Myelin is a fat that coats the nerves and ensures the accurate transmission of information in the nervous system.
