OPT: (a). watershed. (b). Collagen. (c). excretory. (d). trunks. (e). fibrils. (f). soil. (g). Winter. (h). cellulose.

Fact 1: Astem is used to store water by some plants. Fact 2: Some plants also store water in their trunks and stems. Given the two facts above, where do plants store water?
Answer:
(d).