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A vertex of a graph is called pendant if

• its degree equals 0

• its degree equals 2

• its degree equals 1

• it is not isolated

• there is no true answer

A vertex of a graph is called isolated if

• there is no true answer

• its degree equals 0

• its degree equals 2

• its degree equals 1

• it is not pendant

A subgraph of a graph G = (V, E) is

• a graph H = (W, F) where W⋂V≠∅ and F⋂E≠∅

• a graph H = (W, F) where W ⊆ V and F ⊆ E

• a graph H = (W, F) where V⊂ W and E ⊂ F

• a graph H = (W, F) where W ≠ V and F ≠ E

• a graph H = (W, F) where W⋂V=∅ and F⋂E=∅

The union of two simple graphs G1=(V1,E1) and edge set G2=(V2,E2) is

• the undirected graph with vertex set V1 ⋃ V2 and edge set E1 ⋃ E2 such that |E1⋃E2|=|E1|+|E2|.

• the undirected graph with vertex set V1 ⋃ V2 such that |V1⋃ V2|=|V1|+|V2| and edge set E1 ⋃ E2

• the multigraph with vertex set V1⋃ V2 and edge set E1 ⋃ E2 such that |E1 ⋃ E2|=|E1|+|E2|

• the simple graph with vertex set V1 ⋃ V2 and edge set E1 ⋃ E2

• the simple graph with vertex set V1 ⋂ V2 and edge set E1 ⋂ E2

A directed graph differs from a directed multigraph since

• every directed multigraph has multiple edges and has no loops

• every directed multigraph has multiple edges

• every directed graph has multiple edges and has no loops

• every directed graph has loops and multiple edges

• every directed multigraph has loops and has no multiple edges.

A pseudograph differs from a multigraph since

• every pseudograph has multiple edges and has no loops

• every multigraph has loops and has no multiple edges

• every multigraph has multiple edges and has no loops

• every multigraph has no multiple edges and loops

• every pseudograph has no multiple edges and loops

A simple graph differs from a multigraph since

• every multigraph has loops

• every multigraph has multiple edges or loops

• every simple graph has loops

• every simple has loops or multiple edges

• every multigraph has multiple edges

Which of the following simple graphs does exist?

• a simple graph with seven vertices of degrees 0, 1, 1, 2, 3, 4, 6.

• a simple graph with four vertices of degrees 0, 1, 1, 4.

• a simple graph with six vertices of degrees 1, 2, 3, 4, 5, 6.

• a simple graph with five vertices of degrees 1, 2, 2, 2, 3.

• a simple graph with three vertices of degrees 0, 1, 2.

How many edges are there in an undirected graph having 3 vertices each of degree 3 and 5 vertices each of degree 5?

• 34

• 17

• 8

• 16

• 25

How many edges are there in an undirected graph with 7 vertices each of degree 4?

• 7

• 12

• 14

• 28

• 20