Question

dubautia carrri is a species in a family of plants known collectively as the silversword alliance, all of which grow only on the hawaiian islands. members of this alliance exhibit an extraordinary range of phenotypes, with some species maturing into vines and others into shrubs and trees. all species in the alliance descended from a single ancestral tarweed plant that arrived on the islands around 5 million years ago. the tarweeds descendants diversified into distinct species as they adapted to live in the wide variety of habitats found on the hawaiian islands. 3 which choice best states the main purpose of the text? a to indicate the specific tarweed ancestor of all plants that grow on the hawaiian islands and explain why the plants have such varied physical characteristics b to describe the specific habitat where dubautia carrri are found and identify other plants that share a common ancestor with them c to describe the silversword alliance and explain how the plant family became so varied d to advance the claim that all plants on the hawaiian islands are part of the silversword alliance and list possible ancestors of the plants that make up the alliance

Explanation:

• Option A: The text doesn't focus on identifying the specific tarweed ancestor of all Hawaiian plants, just that the alliance descended from one tarweed. Eliminate A.
• Option B: The text isn't mainly about the habitat of Dubautia carrii or identifying other plants with the same ancestor; it's about the alliance and its diversification. Eliminate B.
• Option C: The text describes the silversword alliance (including Dubautia carrii as a member) and explains how the family became varied (descended from one tarweed, diversified into distinct species as they adapted to Hawaiian habitats). This matches.
• Option D: The text doesn't claim all Hawaiian plants are part of the alliance or list possible ancestors; it says the alliance grows only on Hawaii and has one ancestral tarweed. Eliminate D.

Answer:

C. To describe the silversword alliance and explain how the plant family became so varied