In surgery yes. it would hurt without it and nobody would get surgery and surgeons would have no job. <span />
Answer: In most chemical reactions, bonds are both broken and made. Energy is absorbed when bonds are broken, and released when bonds are made. The sum total of the released (negative) energy and absorbed (positive) energy determines whether the overall reaction is exothermic or endothermic.
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The answer is A and D. At first, they are confused with the structure. All they know is the DNA is consists of A, T, C and G. After they know the number relationship, they figure out that base may be pairs(A&T, G&C). Then the X-ray helps them to get the coiled helix structure.
c, 22,800 (4 half lifes, 1/2, 1/4, 1/8, 1/16)