The human immunodeficiency virus (HIV) is a lentivirus (a subgroup of retrovirus) that causes HIV infection and acquired immunodeficiency syndrome (AIDS).AIDS is a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive.he human immunodeficiency virus (HIV) is a lentivirus (a subgroup of retrovirus) that causes HIV infection and acquired immunodeficiency syndrome (AIDS).
The definition of optimal is the most favorable. An example of optimal used as an adjective is in the phrase optimal score, which means the highest score someone can get on a game. most favorable or desirable; best; optimum. Origin of optimal.
The noun estimation refers to a judgment of the qualities of something or someone. In your estimation no boy will be good enough for your daughter. He could be the kindest and smartest person on the planet and you'd still find fault. The noun estimation has its Latin roots in aestimare, meaning to value.. One of the definitions for estimation is an approximate calculation of something's value. If you go to an auction, you can often review a catalog that will have an estimation of the value of each item for sale.