What does 'flourished” in the passage mean?

Read the following passage and choose the correct answer to each of the questions

Until recently, humankind seemed to view the ocean as a source of infinite resources. Its vast size and depth and unexplored frontiers made the ocean appear invulnerable to overexploitation. The truth is that the populations of many species are decreasing at an unsustainable rate, and the number of species listed as endangered from marine life families such as whales, dolphins, manatees and dugongs, salmon, seabirds, sea turtles, and sharks to name a few, are on the rise. The threats to marine species are difficult to perceive because marine animals are not as visible as animals on land. But unfortunately, marine creatures are equally, if not more, vulnerable to problems such as habitat destruction and overexploitation. Shallow water animals that breathe air, like turtles, manatees, dugongs, and whales are often hit by boats and caught in fishing gear. Species such as turtles that lay their eggs on land often lose their nurseries due to coastal development. Animals that have taken millions of years to evolve, that are invaluable to all ecosystems, have and continue to vanish from places where they once flourished.

What does “flourished” in the passage mean?

• A. changed into something unusual
• B. spread all over
• C. failed miserably
• D. grew in a successful way