Yes, extinctions have happened throughout history, they are happening today and will continue to happen in the future.
false :)
false
Sudden changes in environmental conditions.
There have been five mass extinctions in the past 4 billion years on Earth. These events resulted in the widespread loss of species and fundamentally reshaped the evolution of life on our planet.
fossils
The past tense of occur is occurred.
THE PAST Participle of occur is occurred!
The past tense of the word "occur" is "occurred."
The past tense of "to occur" is occurred.
Every single extinction has happened in the past. If an extinction is happening this instant we will not know about it until it is in the past. As and when any future extinctions happen we will not know about it until it is in the past.
The past participle is occurred.
Yes, it is simple past tense.