Answer:
1. IgA refers to the class of antibody, which is witnessed in very large concentrations in mucus secretions.
2. IgD refers to the class of antibody, which is not discharged by B cells, however, is expressed in the naive B cells' surface.
3. IgE refers to the class of antibody, which takes part in the defense against the infections caused by parasites, and also takes part in allergic reactions.
4. IgG refers to the class of antibody that can pass through the placenta.
5. IgM refers to the class of antibody that is the first to appear post-stimulation of B cells.
The correct option is A.
A density independent factor refer to a weather or climate condition, which exert its influence on a population size without regard for the size of the population and its density. Limiting factor refers to any factor that put a limitation on the growth, abundance or distribution of a population. In the question given above, the Hurricane Katrina is a density independent factor because the hazardous event affected all the people that are resident in the affected areas.
the answer would be electrons
Answer:
About 20 kilometers
Explanation:
The biosphere is about 20 km from top to bottom. It has existed for about 3.5 billion years so it's pretty old