This question is simply asking for the advantages which multi-cellular animals have over unicellular organism. There are many advantages attached to being a multi cellular animal, these include:
more complex internal layout which allows for cells specialization and allow multi cellular organisms to carry out more complex tasks than unicellular organism.
Multi cellular organisms such as lizard are able to reproduce sexually, this allow mixture of sex cells from two different individual and leads to longer life span of multi cellular organisms. Also, in term of size, multi cellular organisms are bigger and they can live in a wide variety of environment