Ecology
Ecology studies the life of living things and their environment.
Answer:
One million.
Explanation:
Each kidney contains about one million of nephrons. The nephron is the structural and functional unit of the kidney means that our kidney is made up of nephrons. The main function of nephron is to produces urine in the process of removing waste, toxic and excess substances from the blood. kidney is responsible for the filtration of blood by removing all the waste materials and taken these waste materials to the excretory organs in order to remove from the body.
I believe filtration is the first step in treating lake water.
Hope this helps!!
