Which one does not belong?

Exercise and reference answers

Questions

1. Items

   1. Fire
   2. Earth
   3. Copper
   4. Air

   Odd item

   Copper

2. Items

   1. Proton
   2. Neutron
   3. Electron
   4. Isotope

   Odd item

   Isotope

3. Items

   1. Aristotle
   2. Thomson
   3. Millikan
   4. Rutherford

   Odd item

   Aristotle

Instructions

Tap the item that does not fit with the other three.

Explanation