In the fossil record, there is no evidence of anything living on land before plants. why are plants necessary before more complicated animals can evolve?
a. plants were needed to produce oxygen.
b. plants were not needed.
c. plants were needed to change the soil content.
d. plants were needed to produce carbon dioxide.

The steps in the formation of extrusive igneous rocks are listed below in an incorrect order: 1. rock melts due to high temperature. 2. rock is buried deep under earth's surface. 3. magma is forced out of earth's surface during volcanic eruption. 4. lava cools and crystallizes to igneous rock. which of these best shows the correct order of steps in the formation of extrusive igneous rocks? 1, 3, 4, 2 2, 1, 3, 4 3, 4, 2, 1 4, 2, 1, 3