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.
People who have HIV and donât get treatment almost always die from the virus. But with medication, people with HIV can be healthy and live a long time. Whatâs the difference between HIV and AIDS? HIV is the virus that causes AIDS. AIDS stands for Acquired Immune Deficiency Syndrome. HIV and AIDS are not the same thing. And people with HIV do not always have AIDS. HIV is the virus thatâs passed from person to person. Over time, HIV destroys an important kind of the cell in your immune system (called CD4 cells or T cells) that helps protect you from infections. When you donât have enough of these CD4 cells, your body canât fight off infections the way it normally can.