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 optimality model is a tool used to evaluate the effects of costs and benefits on animal behavior in the natural world. This evaluation allows researchers to make predictions about an animalâs optimal behavior. Optimality modeling is the modeling aspect of optimization theory. It allows for the visualization of the costs and benefits that influence the outcome of a decision and contributes to an understanding of animal adaptations.