You are asked to prepare a short composition and related tasks on the theme of teenage substance abuse for a school awareness folder. Produce a 200-word composition and answer the accompanying items below.

a. Write a composition titled "Substance Abuse Among Teenagers: A Growing Threat" in 200 words.

b. Write a concise 40-word summary of the composition.

c. List four major causes of teenage substance abuse (one-line each).

d. Suggest four concrete measures to prevent substance abuse among teenagers (one-line each).