Calcium
this is because calcium will lose will lose more electrons and is a group 2 metal, copper is a transition metal which is a lower position and more stable than calcium.
The answer is the fourth choice, or Have membrane-bound organelles. Hope this helps you!
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-Belle
<span>You need to consider the valences of the two elements. Potassium is +1; nitrogen is -3. To balance the molecule, you need 3 potassium to one nitrogen, or K3N</span>
