What is the main function of the toxins emitted by the dinoflagellates?

His response was as sharp as a ___________ 

Read the following passage and mark the letter A, B, C, or D to indicate the correct answer to each of the questions from 30 to 34  

     Mickey Mouse, Walt Disney's most famous character, made his screen debut on November 18, 1928, as star of the first sound cartoon, Steamboat Willie. Since his debut, Mickey Mouse has become an international personality whose success laid the financial foundation upon which Walt Disney built his creative organization. Besides being the personification of the Disney Empire, Mickey Mouse has become one of the most universal symbols of the twentieth century.  

     Mickey Mouse was born in Walt Disney's imagination early in 1928 on a train ride from New York to Los Angeles. Walt was returning with his wife from a business meeting at which his cartoon creation, Oswald the Rabbit, had been wrestled from him by his financial backers. Only 26 at the time and with an active cartoon studio in Hollywood, Walt had gone east to arrange for a new contract and more money to improve the quality of his Oswald pictures. The moneymen declined, and since the character was copyrighted under their name, they took control of it. “So I was all alone and had nothing." Walt recalled later. “Mrs. Disney and I were coming back from New York on the train and I had to have something I could tell them. I'd lost Oswald so, I had this mouse in the back of my head because a mouse is sort of a sympathetic character in spite of the fact that everybody's frightened of mice, including myself". Walt spent the return train ride conjuring up a little mouse in red velvet pants and named him “Mortimer”, but by the time the train screeched into the terminal station in Los Angeles, the new dream mouse had been rechristened. Walt's wife, Lillian, thought the name "Mortimer" was too arrogant and suggested “Mickey". A star was born!  

(Source: Michigan Competency)  

Mark the letter A, B, C, or D to indicate the underlined part that needs correction in each of the following questions.  

The Notre Dame Cathedral, was built between 1877 and 1883, is set in the heart of Ho Chi Minh City's administrative center.

The people downstairs can't be making much of a ___________, because I hardly see any customers there.

Mario was trying to ___________ if there was any cinnamon in the apple cake he was eating.