Imagine your body is like the house you live in. Every day, your family creates rubbish. The rubbish builds up until it is put out for the weekly garbage collection. Now, say you put three bags of garbage out, but because one of the collectors was away sick, only two bags are collected. You take the leftover bag inside to be put out again next week. The following week you put on another three bags, plus the leftover bag from last week. But again, only two bags are collected. Imagine this cycle is repeated over the following weeks. This is a simple description of what happens to your body when your kidneys   don't work efficiently. Your body is not thoroughly emptied of waste products. Other areas of the body such as blood pressure and red blood cell production are affected and the _ process that may lead to kidney failure begins. It's not uncommon for people to lose up to 90% of their kidney function before developing any symptoms. There may be no warning signs. This makes early detection   difficult. Kidney's main job is to remove toxins   and unwanted water from our blood. Every day our kidneys clean an average of 200 litres of blood. Kidney failure may be a gradual and silent process, going unnoticed because there is no apparent pain. Research shows that more than 25% of the patients requiring dialysis   do not see a kidney specialist before they have to do so. Some risk factors for kidney disease such as age and genetic make up are out of our control; however, some changes in lifestyle may help prevent kidney damage.Two major risk factors for kidney disease, diabetes   and high blood pressure, have been on the rise over the last few decades.Both conditions are chiefly affected by being overweight and not getting enough exercises, which are the potential risk factors for the kidney disease. The author gives the example of the house we live in to indicate that   _  .
it's safe and harmless for our body to keep some waste it's important for our body to empty the waste in time every day our body will not produce any waste if our kidneys work efficiently it doesn't matter much if the waste in our body is not emptied in time