When setting up a conversion, where does the initial unit go in the conversion factor?

All these conversion factors are equal to 1. If it doesn't seem obvious at first, think about it for a second. Realize that 1 minute is equivalent to 60 seconds. Simply replace 1 minute in the fraction with its equivalent 60 seconds and it becomes clear that 60 seconds / 60 seconds = 1. Numerator and denominator are equivalent; they are just expressed differently.

Explanation:

because u need two or more forms of the same element that contain equal numbers of protons but different numbers of neutrons in their nuclei to form isotopes.

so since they all have the same shape? i mean maybe because m& m and reeses are both chocolates

1 is the answer to this problem