Final answer:
The sound repetition connecting the lines in 'Heat' by H.D. is anaphora, which uses repeated words or phrases at the start of clauses to emphasize a point and create rhythm.
Step-by-step explanation:
The form of sound repetition that serves to connect the lines from "Heat" by H.D. is anaphora, which is the repetition of a word or phrase at the beginning of successive clauses or sentences. This technique is evident in the repeated use of the command 'rend' at the start of the clauses, which creates a rhythm and emphasizes the speaker's intense desire to break through the oppressive heat. Other poetic techniques that involve sound repetition include alliteration, assonance, and consonance, which help to create musicality and reinforce meaning in a poem.