Which of the following substances protects the skin from ultraviolet radiation?
Melanin.
Perspiration.
Sebum.
Keratin.
The Correct Answer is A
Melanin is a pigment produced by cells called melanocytes in the skin.
It protects the skin from ultraviolet (UV) radiation by absorbing and dissipating over 99.9% of absorbed UV radiation.
This helps to prevent DNA damage and other adverse effects of UV radiation on the skin.
Choice B. Perspiration is not correct because it is a fluid produced by sweat glands in the skin that helps to regulate body temperature, but it does not protect the skin from UV radiation.
Choice C. Sebum is not correct because it is an oily substance produced by sebaceous glands in the skin that helps to lubricate and protect the skin, but it does not protect the skin from UV radiation.
Choice D. Keratin is not correct because it is a fibrous protein that provides strength and durability to the skin, hair and nails, but it does not protect the skin from UV radiation.
Nursing Test Bank
Naxlex Comprehensive Predictor Exams
Related Questions
Correct Answer is D
Explanation
Genes are segments of DNA that encode the information for making proteins.
The sequence of nucleotides (As, Ts, Cs, and Gs) in a gene determines the amino acid sequence of the protein. DNA sequencing is the process of determining the sequence of nucleotides in a piece of DNA.
Choice A is incorrect because enzymes are proteins that catalyze chemical reactions, not DNA sequences. Choice B is incorrect because blood types are determined by the presence or absence of certain antigens on the surface of red blood cells, not by DNA sequences. Choice C is incorrect because hormones are chemical messengers that regulate various body functions, not DNA sequences.
Correct Answer is C
Explanation
A control group is a group in an experiment that does not receive the treatment or manipulation being tested and is used as a benchmark to measure how the other tested subjects do.
The control group is used to minimize the effects of all variables except the independent variable.
This allows researchers to determine if changes in the dependent variable are due to the manipulation of the independent variable or if they are due to some other factor.
Choice A. Responding is not the correct answer because it refers to the dependent variable, which is the variable that is being measured in an experiment.
Choice B. Manipulated is not the correct answer because it refers to the independent variable, which is the variable that is being manipulated in an experiment.
Choice D. Variable is not the correct answer because it refers to any factor that can change in an experiment and can include both independent and dependent variables.
Whether you are a student looking to ace your exams or a practicing nurse seeking to enhance your expertise , our nursing education contents will empower you with the confidence and competence to make a difference in the lives of patients and become a respected leader in the healthcare field.
Visit Naxlex, invest in your future and unlock endless possibilities with our unparalleled nursing education contents today