Why do amphibians and frogs seem to appear suddenly after the rain?

Because that's when they are safest from their predators. The predators are still hiding and waiting out the rain.

answer; i believe the correct answer is (replication is not conservative);

correct answer: understand the different control methods available

integrated pest management is an strategy that is based on the ecosystem and try to prevent the pest and the damage caused by them by applying combination of technique like habitat manipulation, biological control and use of resistant varieties.

the main aim of the integrated pest management is not to completely eliminate the pest but to strengthen the ecosystem so that conditions are favorable for plants and unfavorable for pests.