Explanation
Correct answer: B.
Choice B is the best answer because it most accurately states what feature of Hevea brasiliensis is helpful for the process of making rubber. According to the text, this tree species produces latex, which is used to make rubber, and its inner bark contains a "network of tubes" that, when cut, enables the latex to flow out. The text explicitly states that this feature of Hevea brasiliensis is "helpful for the process of making rubber."
Why the other choices are wrong
Choice A
Choice A is incorrect because the text doesn’t mention the quality of the rubber produced from the latex of Hevea brasiliensis or compare its quality to that of rubber produced from other sources.
Choice C
Choice C is incorrect because the text never discusses the climates in which Hevea brasiliensis grows. Moreover, the text mentions only one region where this tree is found: the Amazon rainforest.
Choice D
Choice D is incorrect. Because the text states that Hevea brasiliensis is the world’s "main source of natural rubber," it can be inferred that there is at least one other source. However, the text doesn’t specify whether that other source is also a tree species and, if so, whether that species grows in the Amazon rainforest.