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.
The most common type of mountain is a fold mountain. Fold mountains form when continental tectonic plates are pushed together, like the Himalayas in South Asia. Tectonic plates make up the Earth's crust (both the continents and the ocean floor) and are like puzzle pieces floating around on the mantle below.