Which of the following describes the perfectly competitive industry's supply curve? Multiple choice question. It is the sum of the supply curves of all the firms in the industry and has an important bearing on price It is the sum of the supply curves of all the firms in the industry and does not have an important bearing on price It is the sum of the supply curves of some firms in the industry and has an important bearing on price It is the sum of the supply curves of all the firms in the industry and has an important bearing on output