A fern is a vascular plant that have neither seeds nor flowers. Fern spieces live in the variety of habitats: shady forests, acid wetlands and tropical areas. Tree stratum zone contains the tallest trees. The small tree zone is lower than tree stratum zone. The shurb zone contains schurbs which grow the food for animals. Finally, the herb layer is made up of wildflowers and ferns. Answer: D ) Herb zone.