Answer: Cell.
Explanation: atoms to molecules, cells, tissues, organs, organ systems, organisms
If you are asking the difference between the two words, then a partner means a pair of two people working together on a project or activity, where as a friend is a person in which one has a close bond or relationship with that is platonic.
for which i have been waiting my whole life
The correct answer is c not either other answer
A common noun are words like house. Year