Question

1. geologists discover two layers of rock. the lower layer has sea shells, and the upper layer has land mam the environment?

mammals lived in the ocean first
sea animals and mammals live in the same place
the land used to be covered in water that has since become dry land
seashells were moved to the area

Explanation:

Rock layers form over time, with lower layers being older. The lower layer's sea shells show the area was once underwater, while the upper layer's land mammal remains show the area later became dry land, indicating an environmental change from ocean to terrestrial.

Answer:

The land used to be covered in water that has since become dry land