How can you define domain and motif? Is there any significance in bioinformatics or in proteomics?

Bioinformatics homework

1.How do you think the existence of multidomain proteins relates to complexity in higher eukaryotes?
2 The attached paper is for your reading, if interested. It discussed about structure-based inhibitor.
3.How can you define domain and motif? Is there any significance in bioinformatics or in proteomics?
4.Why Snare complex is important in normal muscle movement?