In many cases, no written record of plant knowledge exists. Recognizing this, Fadiman’s first effort is to record all the information that local people can provide. What does the word “this” refer to?
a. no written record of sustainable and non-sustainable collection of plants
b. the effort to record all the information about Ecuador’s rainforest
c. where and why such differences exist in Ecuador’s rainforest
d. no written record of plant knowledge in Ecuador’s rainforest exists