Please choose the correct answer to the question: An increase in phosphate levels in a lake increases the population of algae in the lake. Increased algae blocks sunlight into the lake and results in a decrease in dissolved oxygen in the lake's water. Which of the following should be expected as a result?

Answer1: Plant populations in the lake increase. Answer2: More predatory birds feed on lake animals. Answer3: Phosphate levels in the lake decrease. Answer4: Fish populations in the lake decline.

Answer format: answer1/answer2/answer3/answer4