Question

Undecayed plants and animals of long ago are:

O cast fossils
O permafrost fossils
original-remains fossils​

Answer 1

that would be original remain fossils :)

Explanation:if the plant is undecayed, that means it almost all intact, and almost nothing would have changed! If I am wrong go ahead and correct me! Have a great day/night :D

Answer 2

permafrost fossils I believe