Please help with answering this question. And show how so i can understand

19. a) Explain why it is not possible to draw a loop-free con- nected undirected graph with eight vertices, where the de- grees of the vertices are 1, 1, 1, 2, 3, 4, 5, and 7. b) Give an example of a loop-free connected undirected multigraph with eight vertices, where the degrees of the vertices are 1, 1, 1, 2, 3, 4, 5, and 7