Coal Mining is considered the most dangerous job in the United States. Mining also possibly releases harmful chemicals in the environment.
Answer:
Replicates can be used to measure variation in the experiment so that statistical tests can be applied to evaluate differences. Averaging across replicates increases the precision of gene expression measurements and allows smaller changes to be detected.
Explanation:
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.
Answer:
Nesting & Foraging behavior
Explanation:
Seabirds are generally tertiary consumers and / or marine predators that, in marine foodwebs, occupy the upper trophic level. They are very well adapted to all marine ecosystems and feed on a variety of prey: from micro-crustaceans to fish and cephalopods.
Generally, seabirds are observed performing a nesting behavior, by laying eggs near the shore, and then are found exhibiting foraging behavior -searching and foraging for prey- in both the coastline and pelagic zone, also known as the open sea.
Seabirds exhibit different foraging behaviors, for example, the <u>surface feeding behavior which involves flying along the surface with their beak in the water. Gulls, albatrosses and petrels are examples of surface feeders.</u>
<u>On the other hand, plunge diving involves preying on fast marine organisms by diving into the water during their flight. Pelicans are example of seabirds who engage in this behavior.</u>
