All bacteria are classified as
a. eukaryotes.
b. prokaryotes.
c. archaea.
d. protista.

The best answer is B - Prokaryotes.

Bacteria do not have a membrane bound nucleus and other internal structures. They have therefore been placed in the class of prokaryotes.

The dominant living creatures on earth are the prokaryotes. They have been able to adapt to nearly all ecological habitats that are available.

Some types of bacteria can cause disease in human beings, animals and even plants. However most are quite harmless.

Other bacteria serve as important ecological agents in that they fix nitrogen in the soil and degrade  cellulose. Soil would not be fertile without bacteria. 

i think it would be b. tissue because an organ system is a group of organs that work together to perform one or more functions. each does a particular job in the body, and is made up of certain tissues.

idk why hjggjhjkhj