Question

multiple-choice question
non-native (exotic) species can become ______ species when they out compete the native species.
extinct
exotic
umbrella
keystone

Explanation:

First, analyze each option:

• "Extinct" refers to species that no longer exist, which doesn't fit as non - native species out - competing native ones wouldn't make them extinct (they are the ones doing the competing).
• "Exotic" is just the term for non - native, and the question is about a new status they gain by out - competing, so this is not correct.
• "Umbrella" species are those whose conservation helps many other species, not related to out - competing native species.
• "Keystone" species play a critical role in an ecosystem, and non - native species that out - compete native ones can become keystone (dominant and influential) in the new ecosystem. Wait, no, actually, when non - native species out - compete native ones, they can become invasive (but since that's not an option, maybe there's a mistake in the options or my initial analysis). Wait, re - checking: maybe the intended answer is that when non - native species out - compete native ones, they can become "keystone" (though more accurately invasive, but among the given options, let's re - evaluate. Wait, maybe I made a mistake. Wait, "exotic" is non - native, "extinct" is gone, "umbrella" is for conservation, "keystone" is a species with a large impact. When non - native species out - compete natives, they can have a dominant impact, so maybe "keystone" is the intended answer? Wait, no, actually, the correct term for non - native species that out - compete natives is "invasive", but since that's not an option, maybe there's a typo or error. But among the given options, let's check again. Wait, maybe the question has a mistake, but if we have to choose from the given options:

Wait, no, perhaps I misread. Wait, the options: maybe the last option is "Invasive" (but it's written as "Keystone" maybe a typo). But assuming the options are as given, let's re - think. Wait, "keystone" species are crucial for the ecosystem structure. If a non - native species out - competes natives, it can become a keystone (dominant) species. So among the options, "Keystone" is the most plausible (even though the accurate term is invasive, but since that's not an option).

Answer:

The correct option (assuming a possible typo and the intended concept) is: Keystone (the option with "Keystone" text, as the other options don't fit. "Extinct" is incorrect, "Exotic" is just the original status, "Umbrella" is for conservation - related, so "Keystone" is the best among the given choices).