请教GWD23-31

According to some botanists, invasive plants are the second most serious threat, after habitat loss, to native species of plants and animals and to the maintenance of biologically diverse ecosystems.

1. threat, after habitat loss, to native species of plants and animals and to the maintenance of biologically diverse ecosystems

2. threat, after habitat loss, to native species of plants and animals and for maintaining biologically diverse ecosystems
3. threat, after losing their habitat, to native species of plants and animals and also to maintenance of biologically diverse ecosystems

4. threat to native species of plants and animals and for maintaining biologically diverse ecosystems, after habitat loss

5. threat to native species of plants and animals as well as to maintaining biologically diverse ecosystems, after losing their habitat

答案是A,我选择的是E，难道是因为E的their指代不明吗？

E的their在句中指代invasive plants,因為邏輯主語就是invasive plants.

as well as並不等同於and.and表示前後對等，as well as則不是.

整句的邏輯應該是invasive plants是僅次於habitat loss外，對ecosystems最大的威脅，用losing

their habitat完全的nonsense.