The elements of an argumentative essay include___________, ____________, ______________, _______________, ________________.
1What are the two ways to organize an argumentative essay featuring counter-arguments?________________ and ________________.
DNA变性时正确的说法是?
A. 肽键断裂
B. 盐键断裂
C. 碱基对之间氢键断裂
D. 疏水键断裂
E. 二硫键断裂
能使DNA分子变性的因素有:
A. 加热
B. 超声波
C. 尿素
D. 中性环境