Answer:
D. This nonfatal disease disrupts the central nervous system (CNS).
Explanation:
Multiple sclerosis is a type of disease that is typically associated with the central nervous system (CNS) such as the spinal cord and the brain. It is mainly caused as a result of the immune system eats up or attack the protective covering known as myelin which protects nerve fibers and as such causing communication problems between several parts of the body and the brain.
In Medicine, multiple sclerosis is also referred to as encephalomyelitis disseminate and it is nonfatal in nature but can be lifelong (long-lasting) or last for a long period of time.
Hence, the statement that correctly describes multiple sclerosis is that, it is a nonfatal disease disrupts the central nervous system (CNS).
<span>The Disengagement Theory is a theory of aging
that refers to a decrease in interactions between an aging person and the
social system he belongs to. The theory suggests that it is only natural and
acceptable for older adults to withdraw from society as aging is an inevitable
process of life. It is formulated by Cumming and Henry in 1961 and is
considered as the first theory of aging that social scientists have developed. It
is one of the three major psychosocial theories that describe people’s
characteristics as they grow of old age.</span>
In the human embryo, the first site of blood formation is the yolk sac. Later in embryonic life, the liver becomes the most important red blood cell-forming organ, but it is soon succeeded by the bone marrow, which in adult life is the only source of both red blood cells and the granulocytes. Their job is to transport oxygen to the body's tissues in exchange for carbon dioxide, which is carried to and eliminated by the lungs. Red blood cells are formed in the red bone marrow of bones. Stem cells in the red bone marrow called hemocytoblasts give rise to all of the formed elements in blood. Erythroid (red blood) cells are the first cell type to be specified in the postimplantation mammalian embryo and serve highly specialized, essential functions throughout gestation and postnatal life. The existence of 2 developmentally and morphologically distinct erythroid lineages, primitive (embryonic) and definitive (adult), was described for the mammalian embryo more than a century ago. Cells of the primitive erythroid lineage support the transition from rapidly growing embryo to fetus, whereas definitive erythrocytes function during the transition from fetal life to birth and continue to be crucial for a variety of normal physiologic processes. Over the past few years, it has become apparent that the ontogeny and maturation of these lineages are more complex than previously appreciated. In this review, we highlight some common and distinguishing features of the red blood cell lineages and summarize advances in our understanding of how these cells develop and differentiate throughout mammalian ontogeny.
