Hi, I have read that the Earth has undergone five ice ages, the latest one is the Quaternary glaciations. I know that in the ice age there are glacial periods and interglacial periods, and we are currently in an interglacial, I want to make sense what is the effect of those succsessive periods on the life on Earth. Because in my text book I read that the soil has grown and become fertile since 20 thousand years ago, since the interglacial period started. But what made this change in the soil? and why it becom suitable for farming? And will we undergo a glacial in the future? And is it a costant thing that the soil become rich and good in the interglacials of all ice ages?