Drip—hiss—drip—hiss fall the raindrops / on the oaken log which burns, and steams, and smokes the ceiling beams. Which technique is being used

Why is it important to include a descriptive subject heading? it in sorting the topics. it the recipient see its importance. e-mail programs won’t allow e-mail to be sent without it. it keeps junk e-mail separate from important e-mail.