Why does cigarette smoke cause a smoker's skin to wrinkle over time?
A) The fibroblast cells that secrete proteins to the skin are degraded.
B) The collagen and elastin matrix that holds skin to muscle is broken down.
C) The ground substance in skin is converted to protein fibers.
D) The nervous tissue that makes skin tighten is destroyed.
B
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In a given strand of DNA, complementary
bases are connected to each other by
a. ionic bonds. b. polar covalent bonds. c. hydrogen bonds. d. peptide bonds. e. nonpolar covalent bonds.
According to most car mechanics, plain water is the best coolant to use in an engine provided the engine is not being exposed to freezing temperatures. If the car is subject to freezing temperatures then a mixture of water and ethylene glycol (antifreeze) is recommended but it does not cool as efficiently as plain water. Why would ethylene glycol reduce the cooling efficiency of water?
A. Ethylene glycol has a higher heat capacity than water. B. Ethylene glycol raises the freezing point of water. C. Ethylene glycol has a lower heat capacity than water. D. Hydrogen bonds in water allow high levels of heat absorption and a large increase in temperature.
If the heritability of criminality is 0.55 in twin studies, what inference can be made about "nature versus nurture" for determining criminality?
a. Children of criminal have a 55% chance of becoming criminals b. Criminal is mainly due to differences in environmental conditions. c. Equal chances exist for any chiold to become a criminal if raised in that environment d. Fifty-five percent of the variability is due to differences in genotypes.
What is the method of action of aldehydes?
A) They disrupt cytoplasmic membranes. B) They inhibit enzymes. C) They damage nucleic acids. D) They disrupt membranes and enzyme function. E) They damage proteins and DNA.