Unlike animal cells, bacteria have a porous cell wall surrounding their plasma membrane. the cell wall may bacteria survive in environment.

 Unlike animal cells, bacteria have a porous cell wall surrounding their plasma membrane. The cell wall may help bacteria survive in hostile environment.

Explanation:

Diferent from cells of higher organisms, the bacterium is faced with an unpredictable and often hostile environment.  

Bacteria  have evolved in order to survive, a sophisticated and complex cell envelope that protects them, but at the same time allows selective passage of nutrients from the outside and waste products from the inside.

a. the production of carbon dioxide through the process of photosynthesis

the correct answer is:

a population changes in response to a change in the environment.