Which statements about scientific explanations are true? I. Scientific explanations must prove that a hypothesis is true. II. Scientific explanations should be based on evidence or data. III. Scientific explanations must have logical and consistent arguments. IV. Scientific explanations should use scientific principles, models, and theories. A. I, II, III and IV B. I, II and III only C. II, III and IV only D. II and III only

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