The correct option is INTRODUCTION OF EXOTIC SPECIES;
Exotic species refers to an introduced specie of an animal which is alien to the ecosystem in which it found itself and which has been transported to that ecosystem either intentionally or by accident. Exotic species normally have varieties of effects on the ecosystem to which they are introduced, sometimes the effect will be good and sometimes the effects could be devastating depending on the particular situation.
Factors which promote diversity include: larger size of the ecosystem, longer growing seasons and climatic stability.<span />
The geologist time scale was formed when scientists studied rock layers and index fossils worldwide. With this information, they placed Earth's rocks in order by relative age. Later, radioactive dating helped determine the exact age of the divisons in the geologic time scale.
This scale is organized by the 4.6 billion years of earth's history into sections based on important changes seen in the geologic record. The largest intervals are called eons, with each eon containing many millions of years.
In precambarian time the processes that affect Earth's surface have lessened the erosion on the surface. Earth was being hit by meteorites every second. Now there is water erosion and there wasn't back then. The surface changes have lessened over time.