One half-life after a radioactive isotope is incorporated into a rock there will be only half of the original radioactive parent atoms remaining and an equal number of daughter atoms will have been produced.
The fertilizers used by farmers can have negative effects on aquatic ecosystems because there is every possibility that the runoffs from the fields can create an algal bloom in the nearby water body. This algal bloom can have a very negative effect on the living organisms of the aquatic body. I hope it helps.
Answer:The second one im sure
Explanation: