What is the biggest difference between grasslands and deciduous forests? a
Deciduous forests have less biotic factors than grasslands.
b
Grasslands receive less precipitation than deciduous forests.
c
Grasslands are only found near the polar regions.
d
There are only biotic features in the grasslands.

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that's what i got you can count the number of atoms

d

explanation:

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