Aids is one of the disease that damage little by little the immune system until the human body die.
Cell is the living blocks of life. They form the structural
and the functional unit of our life, that is a group of cell
forms tissue, a group of tissue forms organ, a group of
organs form organ system and finally a group of organ
systems form a complete organism / individual.
And there are two types of cell
1/ eukaryotic cell ( consists of the plant cell and the animal
cell )
2/ prokaryotic cell (... I don't know man )
A converging lens focuses the diverging, or blurred, light rays from a distant object by refracting (bending) the rays twice. ... This double bending causes the rays to converge at a focal point behind the lens so that a sharper image can be seen or photographed.
(Thus making the vision clear)