In immunology two types of immune response are described depending on whether there is prior contact with the antigen.
• At this first contact, only lymphocytes with receptors specific to the antigen in question are stimulated and lead to the production of antibodies capable of neutralizing it. The lymphocytes capable of recognizing a specific antigen are very few and the production of antibodies - of low intensity and limited duration - is detectable only after a period of latency of several days. This is called the primary response. The specificity of the resulting seropositivity, however, makes it possible to detect contamination (seroconversion).
• Upon re-contact with an antigen that has already triggered a primary response, specific antibody production is found to increase rapidly after a short latency period. The secretion of IgG then reaches levels much higher than those observed during the primary response, while that of IgM is of the same order. This early and intense response, called secondary response, most often results in the destruction of infectious agents before any clinical sign.
• Many centuries before the discovery of microbes, it was noted that people who developed a contagious disease without death were then specifically immunized against the disease, without being protected against others.
• The ability to react appropriately to an already received stimulus supposes the existence of a memory. The immune memory is based on the existence of memory B and T lymphocytes, resulting from the clonal expansion due to the first contact with the antigen. Their lifespan is significantly higher than that of other lymphocytes and their high reactivity gives its rapid and intense character to the secondary response.
False
Nitrogen and sulfur dioxide are acidic oxides in nature. The burning of fossil fuels and other sources are responsible for addition of these oxides in the atmosphere of earth. These oxides mixed with water vapor causes acid rain. Being acidic in nature they will have low pH value. Therefore, greater the concentration of sulfur and nitrogen oxides, will lower the pH value of precipitation.
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A derived character refers to a particular character that is shared by members of a particular population. Genes are considered to be derived characters because THEY ARE TRANSFER FROM GENERATION TO GENERATION FROM PARENTS TO THEIR OFFSPRING. Genes are derived from the DNA molecule of the parents and these are passed to their offspring during the process of cell division in reproduction.
The answer is C
The more plants there are, the more consumers there are. If there aren't enough plants, the consumers have no way of getting energy, and therefore cannot survive. The species also matters, because certain species of plants can only be eaten by certain species of consumers.
<span>the Individuals with delusional disorder will have delusions but they don't have hallucinations, thought disorder, mood disorder, or significant flattening of affect. schizophrenia patients will loose the touch with the reality and they will have hallucinations etc.</span>
