In this task, find the most appropriate number to replace the blank (indicated with _ ) and express it in words.
--------
Question: Plazas have _ accumulations of rubbish but are covered with even layers of mud bricks and plaster.

Answer: no


Question: Every drug has _ names, a chemical name, a brand name, and an official name.

Answer: three


Question: Veterinarians use _ primary methods to fight fleas and ticks.

Answer:
two