Cnidarians were the first phylum that scientists saw tissue level organization in. Tissue level organization meaning cells all of one type start to function in a unified way.
I don't know exactly what you mean but the size of a group affects its defense because there is a larger group. Therefore, more people would be protecting it, adding more to its defense.
The lack of access to the healthy food has caused the growth of Sebastian to slow down. In the case healthy food is provided to him, he can grow into the size he was genetically suited to. This process is known as the canalization. Canalization term is used as the measure of the ability of any given genotype to result in the same phenotype in-spite of the environmental variability.
Potential energy or stored energy.
