Homeostasis is the
a) cooperation of body parts to form tissues, organs, and systems
b) correlation of structure and function
c) idea that all vertebrates are built in a similar way
d) maintenance of a relatively constant and optimal internal environment
e) exchange of materials with the surrounding environment

Pls me i need this ! each cell has genes activated depending on it's job and what kind of cell it is. it is the presence of that causes the repressor protein to fall off and unblock the gene on the lac operon. if a gene is turned on then it is being an additional circular chromosome found in some bacteria that is used in genetic engineering.