A geographer who studies how people learn to live with nature's challenges, like cold weather, most often studies which of the six essential elements of geography? six essential elements of geography?

Maybe a horizontal because its a pattern

When a lake, river or other aquatic  system  becomes  eutrophic, it can have serious negative effects on other organisms like fish, birds and even people.if an algal bloom is so bad that it causes wide-spread death  in  the  water, the organisms that die will all sink to the bottom and start to decompose.