Many of the signaling pathways used for signaling between cells in complex multicellular organisms first evolved in:
A)unicellular eukaryotes.
B)simple multicellular eukaryotes.
C)unicellular prokaryotes.
D)simple multicellular prokaryotes.
E)complex multicellular prokaryotes.

Question

Quizplus · Accepted Answer

Signaling pathways are important for communication between cells in complex multicellular organisms. However, many of these pathways first evolved in unicellular eukaryotes, as these organisms also need to communicate with their environment and with other cells. For example, the cAMP signaling pathway, which plays important roles in various cellular processes and is conserved across many eukaryotic organisms, was first identified in the unicellular eukaryote Dictyostelium discoideum. Therefore, choice A is the best answer.

Many of the Signaling Pathways Used for Signaling Between Cells