a,ta co 2A+2G=6000 (1)ma hieu giua nu loai G voi nu ko bo sung la A ->G-A=600 (2) Tu 1 va 2 -> A=T=1200 ;G=X=1800 b, chieu dai gen la 6000:2.3,4=10200 (A0) Khoi luong gen 6000.300=1800000(dvc) chu ki xoan gen 6000:20=300 lien ket H co trong gen 2A+3G =1200.2+1800.3=7800(H)