1.Which group of numbers can divide 54 with no remainder? A. 1, 2, 5, 7, 12,54
B. 1, 2, 6,9, 27,54
C. 2, 4, 6, 8, 26, 54
D. 1, 2, 7, 8, 29,54

percent abundance for cu-63 can be shown as:

63 x + 65 (1-x) = 62.9296

65 - 62.9296 = 2 x

x = 1.035

thus, percent abundance for cu-63 is 1.035

percent abundance for cu-65 can be shown as:

63 x + 65 (1-x) = 64.9278

65 - 64.9278 = 2 x

x = 0.0361

thus, percent abundance for cu-63 is 0.0361

the mass spectrum of cu-63 showing the intense peak as, this isotope is found in nature more abundantly around 92.38 % in comparison to cu-65 which is found 62.58 % naturally

they are called fossil fuels