Question

which of these is a result of ocean acidification?
a. the exoskeletons of sea creatures become weaker.
b. seawater becomes much saltier.
c. coral reefs increase in size across the ocean.
d. the ocean absorbs carbon dioxide.

Explanation:

Ocean acidification occurs when the ocean absorbs carbon dioxide (\(CO_2\)), which reacts with seawater to form carbonic acid (\(H_2CO_3\)). This lowers the pH of the ocean. Many sea creatures, like corals and shell - forming organisms, have exoskeletons made of calcium carbonate (\(CaCO_3\)). In more acidic water (\(H^+\) concentration increases), the reaction \(CaCO_3 + H^+
ightleftharpoons Ca^{2 +}+HCO_3^-\) is shifted towards the right, making it harder for these organisms to build and maintain their exoskeletons, so the exoskeletons become weaker.
Seawater becoming saltier is more related to processes like evaporation and runoff of salts from land rather than acidification. Coral reefs generally do not increase in size due to acidification; instead, the acidification can damage them. The ocean absorbing carbon dioxide is a cause of ocean acidification, not a result.

Answer:

A. The exoskeletons of sea creatures become weaker.