Flu-like Illness. One of the earliest HIV symptoms in men is a severe 'flu-like' illness, known as the 'seroconversion illness.'. Seroconversion is the point in time where a person's blood is converted from being HIV negative to HIV positive, by the production of antibodies.
Erosion causes the surface of mountains to be younger than the rocks that form the mountains themselves. Glacial processes produce characteristic landforms, such as pyramidal peaks, knife-edge arÃªtes, and bowl-shaped cirques that can contain lakes.
Grasslands develop wherever rainfall is not high enough to produce a forest nor light enough to form a desert. There are few trees in true grasslands, either because the climate is too dry or the soils are too poor. In other areas, grasslands develop because grazing and browsing by wild animals, frequent fires, or both, prevents tree seedlings from growing.