Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 31 to 35.

A few months ago, a group of scientists warned about the rise of “extinction denial,” an effort much like climate denial to mischaracterize the extinction crisis and suggest that human activity isn't really having a damaging effect on ecosystems and the whole planet. That damaging effect is, in reality, impossible to deny. This past year, scientists and conservation organizations declared that a long list of species may have gone extinct, including dozens of frogs, orchids and fish. Most of these species haven’t been seen in decades, despite frequent and regular expeditions to find out if they still exist. The causes of these extinctions range from diseases to invasive species to habitat loss, but most boil down to human behavior. One of the first papers of 2020 to report any extinction announced the probable loss of 17 percent of Bangladesh’s 187 known orchid species. Some of these still exist in other countries, but even regional extinctions (or extirpations, as they're called) tell us that we’ve taken a toll on our ecological habitats. A similar paper published just days later suggested that nine more orchid species from Madagascar may have also gone extinct. One of the few extinctions of 2020 received much media attention, and it’s easy to see why. Handfish are an unusual group of species whose front fins look somewhat like human appendages, which they use to walk around the ocean floor. The smooth species, which hasn’t been seen since 1802, lived off the coast of Tasmania and was probably common when it was first collected by naturalists. Bottom fishing, pollution, habitat destruction, bycatch and other threats are all listed as among the probable reasons for its extinction. Even though the local fishery collapsed more than 50 years ago, the remaining handfish species are still critically endangered, so this extinction should serve as an important wake-up call to save them. (Adapted from https://www.scientificamerican.com/)

Which of the following could be the main idea of the passage?