Trees have woody stems covered with what?
Options:
- (A) food and shelter
- (B) smooth ridges
- (C) looseness
- (D) protective layer
- (E) Organic compounds
- (F) plastic sheet
- (G) heat energy
- (H) thin metal OK. Let's think hard:
Trees have woody stems covered with bark. During the stripping, the protective layer of inner bark is removed. Trees have woody stems covered with a protective layer.
So, the final answer is (D).