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.
1 The higher area is sometimes called a horst and the lower a graben (see the picture below). 2  The Sierra Nevada Mountains in the western United States are fault-block mountains. 3  Volcanic mountains-Mountains that are caused by volcanic activity are called volcanic mountains.