Because pioneer species are the first to return after a disturbance, they are the first stage of succession, and their presence increases the diversity in a region. They are usually a hardy plant, algae or moss that can withstand a hostile environment.
Answer:
The answer to the question: Class II MHC proteins are found on which of the following cell types, would be: on macrophages and lymphocytes, particularly T-Cells.
Explanation:
MHC, or Major histocompatibility complex, is a very important part of the immune response that the body gives against an invading pathogen, or other foreign substances. There are three types in the human body, Class I, Class II and Class III and each of them will play a role on the cellular membrance of different types of cells and mediate different types of responses. In the human body, this histocompatibility complex is best known as HLA, or human leukocyte antigen, and it will ensure the recognition, or non-recognition of substances, tissues, and other organisms, by the human immune system. Class II, as mentioned before, are most usually found on the immune cells macrophages and lymphocytes, and they are the ones responsible for presenting antigens to these proteinic antibodies so that the immune cells can initiate a proper immune response.
<u>Answer</u>:
There are a number of lipids that are found in foods and contribute to various functions in the body. Triglycerides are the most common lipid found in food and in the body; they consist of a <u><em>Glycerol</em></u><u> </u>backbone attached to three fatty acids.
Fatty acids are classified based on the degree to which the carbon chain is saturated with <u><em>Hydrogen</em></u>
A fatty acid is <u><em>saturated </em></u>if it contains no carbon-carbon double bonds, <em><u>polyunsaturated </u></em>if it contains two or more carbon-carbon double bonds, and<em><u> monounsaturated </u></em>if it has only one carbon-carbon double bond.
The unsaturated fatty acids can exist in one of two structural forms: the <em><u>trans </u></em>form occurs when hydrogens on both carbons forming the double bond lie on opposite sides of that bond.
When hydrogens on an unsaturated fatty acid lie on the same side of the carbon-carbon double bond, a <u><em>cis </em></u>formation exists.
Answer:
Option A, Ohio River and the Missouri River
Explanation:
The historical evidences clearly indicate that Ohio River did not exist before the last ice advances. Before Ohio and Missouri river, the major glacier drainage of the east-west direction happens in Teays River. When ice of the glaciers blocked the Teaya river valley, then the Ohio was formed.
Like Ohio, Missouri river did also not exist before Pleistocene and during that time the largest drainage in North America take place in the Hudson's Bay
Hence, option A is correct
There is a valve at the meeting point between each ureter and the bladder prevents the back flow of urine from the urinary bladder to the kidney
