We still gave the boy another chance ______he made some mistakes.
A:though
B:when
C:unless
D:because
某一DNA分子含有1000个碱基对,其中含有A600个.该DNA分子进行第n次复制后,消耗周围环境中含C的脱氧核苷酸3200个,该DNA分子已经复制了( )
a÷b=c(a,b都大于0),当b<1时,( )
鱼、家兔、柳树的结构和功能的基本单位是( )