Answer
Some adults abuse children, neglect,sexual,violent etc.. or engage in criminal or immoral behavior. Their children need to be accommodated away from the parents and the harm being inflicted upon them. This is usually with foster carers. When the parents change their behavior the child will be able to return to the parents. Parental responsibility stays with the parents. If the parents fail to demonstrate change then the authorities may permanently remove the child from the parents at which time they may be freed for adoption and parental responsibility moves to the new parents. Usually when a child is with foster carers the child will maintain some contact with the birth family as the aim should be to return a child to its parents so long as the child will be safe from harm.
AnswerWhilst you should not foster for the money, there should be generous payments to allow people to do it professionally and to not have to work on top of looking after a foster child. Many children who have been abused need to work through the issues and have a supportive rewarding person to help them through it. The work is demanding and emotionally draining and is not at all like having your own children.ANSWER
Foster care is the government taking a child from their family, some times for legitimate reasons, more times not, and placing the child in "foster homes" where people who generally are retired or do not work are paid on a per child basis to provide a "home like" environment.