Grass Anatomy: Roots & Stems. A grass plant is composed of a root, a stem, leaves and a seed head. The root is fibrous, or composed of many small roots that move out in all directions.The stem, or culm, starts out a single section but develops nodes and internodes that segment it along its length.eaves & Seed-heads. Grass leaves emerge from nodes on the stem, with the newest growing on the opposite side from an older leaf below it. A single leaf is composed of a blade, sheath, ligule, auricle and collar.
HIV is the cause of the spectrum of disease known as HIV/AIDS. HIV is a retrovirus that primarily infects components of the human immune system such as CD4+ T cells, macrophages and dendritic cells. It directly and indirectly destroys CD4+ T cells.
AIDS, and HIV, are acronyms. AIDS stands for acquired immune deficiency syndrome. People who have AIDS have an increased susceptibility to life-threatening infections, cancers, and neurological disorders. HIV, or human immunodeficiency virus, causes AIDS. HIV can be transmitted through blood transfusion, sex, contaminated hypodermic needles, childbirth, and breastfeeding. HIV destroys the important cells in the human body that fight disease and infection.