Which sentence describes how a unicellular organism gets oxygen? A. It contains individual specialized cells that carry oxygen.
B. It contains specialized cells that combine into tissues that carry
oxygen.
C. It has a respiratory system that takes in oxygen.
D. It takes in oxygen through its cell membrane.

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.