The first simple, one-celled organisms that developed during the precambrian era are called a. trilobites b. prokaryotes c. stromatolites

B. Prokaryotes

On the basis of the fossil evidences found the prokaryotes including the bacteria and archea were the first single celled organisms, which were expected to be present in the 3.5 to 3.8 billion years ago typically in the Precambrian Period. On the basis of the fossil evidences obtained these organisms were abundantly present.