The superior boundary of the spinal cord is at the level of the

q: compare the parts of a cell and the cell as a whole to another common nonliving system (i.e., a car, a city,

a:

comparing this to the inside of a food building/company.

all cells are surrounded by a plasma membrane, which protects the cell from its environment, keeping toxic substances out of the cell. it regulates which molecules are allowed to enter and exit the cell.

regulates all cell activity such as cellular metabolism, and growth in addition to storing and maintaining the cell's dna for transcription and replication. determines what proteins to make.

contains the organelles; site of most cell activity

the place where ribosomes do their working activity.

builds the proteins.

prepares proteins for use or export.

responsible for breaking down and absorbing materials taken in by the cell.

maintains cell shape.

transforms one form of energy into another.