If someone with HIV is diagnosed with one of these opportunistic infections (even if the CD4 count is above 200), he or she is said to have AIDS. AIDS usually takes time to develop from the time a person acquires HIV--usually between 2 to 10 years or more.
It has been thought that the wheel was invented in 8000 B.C but the oldest discovered wheel dates back to 3500 B.c. It was discovered in Mesopotamia (nowadays in Iraq). Below are the timelines of wheels and its usage in different era.
âThe wheel-and-axle concept was the real stroke of brilliance,â says anthropologist David Anthony. That idea required extreme finesse, which only metal tools could adequately provide. However, these didnât become widespread until around 4000 BCE, hence our delay.