The fact that volcanic rock has often been found early in the rock record but less frequently in later rock layers suggest to scientists the following conclusion about early earth: <span>volcanic activity was more common in the past than it is today.
</span>Besides volcanic activity in general, also huge volcanic eruptions<span> were much </span>more common than today<span>.</span>
Answer: Cropping patterns
Explanation: refers to proportion of area under different crops at different points of time. It also indicates the time and spatial arrangement or sequence of crops and / or fallow in a particular land area.
