Answer:
brothers and sisters don't look exactly alike because everyone (including parents) actually has two copies of most of their genes. And these copies can be different. Parents pass one of their two copies of each of their genes to their kids.
U can hear them talking about you you can see them laphing and snickering
Pollutants can be flushed through a river system and move on downstream, but will remain longer in ponds and lakes. Any organism that come in contact with the contaminated water are harmed by it.