Why are cells called the building blocks of an organism? They are visible to the naked eye.
They are made from nonliving materials.
They are the basic unit of life.
They are able to generate new cells.

They are the basic unit of life!

Explanation:

Basically, without these millions of cells that us humans and animals have, we couldn’t exist. They hold so many core features that make up any living thing on this earth. Cells are the structural, functional, and biological units of all living beings.

Hope this helps!

the answer is:  

he is voicing feelings shared by all humans regardless of race.

in paul laurence dunbar's poem "we wear the mask," he replicates the words mask and we to emphasize how people in general -not just black americans- hide their true feelings. he suggests the masks cover people's faces and eyes, which are the main parts that display their emotions. he also thinks people's pain conceal behind those masks, so that they cannot see reality and nobody is able to see one another's sorrow.