Last step in wastewater treatment is a process A)Chemical

B)Biological

C)Physical

D)Mechanical

ps for aneetasarah and mmschulzul . ik you copy paste from the internet for my last questions

Abird flies by moving its wings up and down. which two systems are most directly responsible for the movement of a bird's wings? a. skeletal and muscular systems b. respiratory and muscular systems c. skeletal and digestive systems d. respiratory and digestive systems