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.
Mountains and valleys form in many ways. Two types of tectonic forces can result in mountains and valleys: compression (squishing) and extension (pulling apart). These forces commonly associate with mountain building but also form valleys. Compressing continents occur when two continents collide.