Impressions of leaves are recognized evidence of what pre-existing

The correct answer is - plants.

The impressions of leaves are a recognized evidence about the existence of plants plants in the geological past of the Earth, at least from certain periods onward.

The leaves themselves are very easily disposable, so it is pretty much impossible for them to be preserved in their natural form, or at least close to it. On the other hand, in certain conditions, the leaves that were disposing, managed to leave impressions, and they were kept in certain types of rocks, mainly sedimentary ones, thus providing us with evidence of their existence in the past.

true. earthquakes are felt whenever there is a slip around a fault in the rocks below the earth. this reorientation of faults create sesmic waves and is known as earthquake, the severity of which is measured in richter scale. these are more prominent in hilly regions as the rocks usually form faults to balance the pressures on it.

question

which are human systems?

the amazon rain forest

the appalachian trail

the george washington bridge

the himalayas

the hoover dam

the north american free trade agreement