Which choice most logically completes the text?

Source Texts

Text

Introducing a new species into a delicate ecosystem can often be harmful. The zebra dove and other fruit-eating birds have established themselves on the Hawaiian island of Oahu after being brought there in the last 150 years. Many plant species on the island rely or on the activity of fruit-eating birds to maintain and increase their populations. In recent studies, zebra doves have been found to spread seeds of native forest plants that are at risk of extinction, such as the mamaki shrub and the alahee tree, suggesting that _blank

although non-native birds initially damaged the plants in Oahu's ecosystem, they are now proving useful to them.

non-native birds have had both positive and negative effects on Oahu's native plants.

non-native birds, such as the zebra dove, are unlikely to eat fruits from non-native forest plants on Oahu.

rather than harming Oahu's ecosystem, some non-native birds provide an important benefit on Oahu.