State the function of nitrogen fixation

Plants need nitrogen in order to grow. Nitrogen is abundant in the earth's atmosphere, but plants cannot use it in that particular form (nitrogen gas). Certain bacteria which reside on some plant roots are able to change atmospheric nitrogen into a form that plants can use (ammonia).

i took a test for bio that had this question and these were the correct answers, not sure if this is any now lol

the nervous system and the muscular system work together.  

sweat reaches the surface of the skin and evaporates into the air.

muscles underneath the skin relax, causing hair on the skin to lay flat.