Question

1. in a riverbank, the bottom layer has no fossils, the middle layers contain small plant fossils, and the top layer contains large tree fossils. what does this sequence suggest?

trees existed before smaller plants
plant life became more complex over time
all plants appeared at the same time
fossils are randomly arranged

Explanation:

Rock layers form over time, with lower layers being older than upper layers. The sequence (no fossils → small plant fossils → large tree fossils) shows plant life developed from simpler/non-existent to more complex forms as time passed. The other options contradict this fossil layer logic: trees are not older than small plants, plants did not appear at the same time, and fossils are not randomly arranged here.

Answer:

Plant life became more complex over time