Which structure evolved in cells approximately one billion years ago that allowed for the forming of more complex, multicellular organisms?

we would need to see the picture to answer it

that scientist would be robert hooke

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.