A(n) defines a two-dimensional shape.

An outline is being defined as a 2 dimensional shape which is the answer. The outline also known as the list being arrange to portray the hierarchical relationship and known as a tree structure. It is used in order to portray the main points or a topic in a subject.

Generally spontaneous human combustion is something that still bewilders some, human combustion happens very rarely and doesn't affect the surrounding areas, so unless you want to set your self on fire, human combustion will remain spontaneous and very rare.

Answer (b) create a social media account and share clips of their recordings;