Answer:
When carbondioxide gas is emitted from vehicles and industries and goes upward in the atmosphere. The carbondioxide gas combines with the rain water forming an acid called carbonic acid and make the rain acidic.
When rainfall occurs this acid comes to the ground and ocean and adversely affected the living organisms due to acidic nature. The marine animal's body comprise of shell and skeleton. This skeleton and shell are made from calcium, when acidification of ocean water occurs, the calcium dissolved and the body of animals are destroyed.