Choose the correct answer to complete the paragraph about the acceptance of the heliocentric model. In the second century BCE, the Greek astronomer Ptolemy tried to explain the backward movement of the planets by using a solar system model that included . For centuries, this was the accepted model. During the Renaissance, Nicholas discovered the old heliocentric model of Aristarchus. In Aristarchus’s model, the rising and setting of the Sun was explained by the movement of the .

the first blank is epicycle.

the second blank is Copernicus

the third blank is earth

gravity causes stares to cluster i think so

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