1. I belive the answer is B.They can grow large
Multicellular organism will be connected with each other. This will allow them to form big and well coordinated organs. Multiple neuron can form a long fiber that stretch from the brain to the end of the every body part.
The cell should not be the same as it could differentiate into a more specific cell. The cell should not reproduce quickly as their growth will be regulated. The cell also doesn't have to do all function by itself as they could rely on other cells.
2. I believe the answer is: A. They can form complex organ systems
Multicellular organism could have a well differentiated organ and form an organ which have specific function. This will allow them to do a complex work that could not be achieved by one cell. Kidney could do filtration, absorption and reabsorption which could be achieved by multiple structure formed by different kind of cells.
