Задайте вопросы к каждому предложению: the passenger pigeon is only one of the many plants and animals that once lived on our planet and have become extinct. extinction has been going on since life began on our planet. but today extinction is happening faster than ever before. i feel very concerned about this and wonder what can be done to stop it?
Since when has extinction been going on?
What is happening today faster than ever before?
Why do I feel concerned and what do I wonder?