Read the following passage and answer the questions

Individualised pacing is one of the major objectives of programmed instruction. This helps students to follow the instructional materials according to their own level of mastery. There are structural as well as functional means of programming instructions. Conventionally, successive approximations are used as a structural means. A sequential design ensures that each approximation of instruction is mastered before the next one is presented. Functional means consists of making reinforcement contingent on students' responses. To make students respond, the techniques of prompting, priming etc. are used as antecedent programming.