Single-celled animals that live in freshwater have a vacuole that contracts regularly to remove excess water. Single-celled plants that live in freshwater do not have a similar vacuole. Which statement explains why only these animals need this vacuole?
1) Animals need to remove excess water to maintain osmotic balance.
2) Animals need to remove excess water to prevent cell bursting.
3) Animals need to remove excess water to maintain cell shape.
4) Animals need to remove excess water to regulate cell temperature.