Which verb form is used to indicate the progressive tense? verb + -ed be + verb + -ing have + been + verb + -ing have + verb + -ed the answer is b

"dyed plant fibers have been found at dzudzuana cave in georgia, dating back to 30,000 years ago." a good paraphrase of this sentence should include: a. how the dyed plant fibers were located within the different caves. b. how old the dyed plant fibers are at dzudzuana cave in georgia. c. the types of plant fibers found in dzudzuana cave in georgia. d. the types of dyes made from plant fibers thousands of years ago.