<span>The skin is the largest organ of the body, </span><span>area of about 20 square feet
</span><span>The skin protects us from microbes and the elements, helps regulate body temperature, and permits the sensations of touch heat and cold.</span>
.......is secreted into the bloodstream, whereas _____ is secreted into mucus such as gastrointestinal fluid, colostrum, saliva, tears, and sweat:
a. Monomeric IgM; pentameris IgM
b. Monomeric IgA; dimeric IgA
c. Monomeric IgA; dimeric IgM
d. Dimeric IgA; monomeric IgA
Answer:
b. Monomeric IgA; dimeric IgA
Explanation:
IgA is a class of antibodies that are found mainly in body secretions. In sweat, tears, saliva, mucus, breast milk, and gastrointestinal secretions, IgA is secreted as a monomeric antibody. Smaller quantities of this class of antibodies are also present in blood and lymph. However, IgA is present in a dimeric form in the bloodstream. It makes up 10–15% of all antibodies in the blood. The main function of this class of antibodies is to give localized protection of mucous membranes against bacteria and viruses.
Ribosomes and mitochondria
Fossil fuels represent carbon storage areas. Carbon that is locked in these fossil fuels does not cycle through the Earth. When humans burn fossil fuels, the stored carbon is released into the atmosphere as carbon dioxide. The carbon is then free to cycle through the Earth and can upset the natural balance of the carbon available, changing the way that processes occur on Earth.
<span>
</span>
In eukaryotes, the first amino acid in a growing polypeptide chain is always methionine because the only codon for this amino acid is also the start codon.