TOEFL Reading: ETS-TOEFL阅读机经 - SNZ51L452Q028TCZL$

According to paragraph 4, what information can be learned from the deliberate shedding of branches by the trees? A. Limiting the size of branches being shed to comparatively small ones B. Forming a new layer of wood to seal the wounded area immediately after shedding C. Shedding leaves at the same time that branches are being shed D. Forming a layer of protective tissue before branch shedding begins