By what process do plants convert nitrogen gas into usable ammonia?

Nitrogen fixation

In "Alice in Wonderland", who celebrates an unbirthday? Who portrayed disgraced figure skater Tonya Harding in the film "I, Tonya"? Who played musical prodigy Andrew Neiman in the movie "Whiplash"? Who scored the first basket in NBA history? What do we call it when animals shed their skin periodically?