Question

pteropods are small swimming snails with thin, delicate calcium carbonate shells. these animals are thought to be especially vulnerable to ocean acidification due to calcium carbonates susceptibility to dissolution at lower ph values. victoria l. peck and colleagues recently found that the periostracum (a protective coating on pteropods’ outer shells) prevents this dissolution when intact. moreover, the team was surprised to discover that even when the periostracum is breached, pteropods can still mitigate damage by rebuilding the inner shell wall. 8 mark for review which choice best describes the main purpose of the text? a to call for additional research on biological mechanisms that improve pteropod survival rates b to discuss a conclusion drawn in a study of calcium carbonates role in protecting the periostracum of pteropods c to address some of the ways ocean acidification has altered pteropod behavior over time d to present findings that suggest that a concern about the effects of ocean acidification on pteropod shells may be unwarranted

Explanation:

• Option A: The text doesn't call for additional research; it presents existing study findings. Eliminate A.
• Option B: The study is about pteropod shells and their response to ocean acidification, not calcium carbonate protecting the periostracum (the periostracum protects the shell). Eliminate B.
• Option C: The text focuses on shell protection mechanisms, not pteropod behavior alteration. Eliminate C.
• Option D: The text states pteropods were thought vulnerable to ocean acidification, but a study found their periostracum and shell - rebuilding mitigate damage, suggesting the concern about shell damage may be unwarranted. This matches D.

Answer:

D. To present findings that suggest that a concern about the effects of ocean acidification on pteropod shells may be unwarranted