Question

your body is made up of over 30 trillion cells. but you didnt start out that way. all humans begin as a single cell! that first cell grows and divides to form more cells.
a human begins as a single fertilized egg cell known as a zygote.
a teenage human is made of trillions of cells.
as the human body grows and develops, cells become specialized to do different jobs. these different types of cells are the building blocks of the organ systems that keep us alive.
complete the paragraph.
humans start out as . as humans develop, they cells. cells specialize to perform jobs in the body.

Explanation:

The text states humans begin as a single fertilized egg cell called a zygote, grow into organisms with trillions of cells, and these cells specialize for distinct roles.

Answer:

Humans start out as a single zygote (fertilized egg cell). As humans develop, they grow into trillions of cells. Cells specialize to perform different, specific jobs in the body.