Answer:
Problem/solution.
Step-by-step explanation:
A problem/solution text structure is when a passage is organized in such a way that the dilemma is provided or expressed, followed by what can be done to remedy that. In other words, it is a text structure where a problem is given, followed by a possible solution for that problem.
Likewise, in the given passage, the problem is expressed first. The problem is that of the alarming disappearing rate of chimpanzees. This is then followed by a probable solution, like saving rainforests and woodlands.
Thus, the text structure is a problem/solution structure.