"The Amish population in Lancaster County, Pennsylvania has a high rate of genetic dwarfism because of low genetic diversity. This high rate of dwarfism can be traced back to the small number of European immigrants that started the population in North America. This is an example of one of the processes that allows genetic drift, which is known as"

Founder effect

Explanation:

Genetic drift is the process of change in allele frequency in a population because of chance increase or decrease in number of particular alleles in that population. It can be caused due to may reasons like founder effect, bottleneck effect etc.

Founder effect is a phenomena where a small group of individuals migrate from the original population to some other area and start a new population. The new population will all result from this small founder population. So if by chance some alleles were present more in the founder population, the new population will also show high frequency for it. As a result the allele frequencies in the new population can differ from the original first population.

Here, the Amish population in North America was settled by a small number of immigrants from Europe. Among those immigrants many had alleles for genetic dwarfism. So when this small population grew in America, genetic dwarfism also became prevalent in them.

the "dirty dozen" chemicals banned in an international treaty are formally known as persistent organic pollutants, or pops. the united nations environment program provided this background on what they are and what they can do to humans and wildlife.

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it has to be understood that the sea water contains a huge amount of sodium and chlorine ions and if they enter the cell of the atlantic cod fish, the cell will shrivel and the fish will die. to avoid such a condition, the fish uses active transport for the purpose of removing the ions against the gradient.

explanation:

the atlantic cod is not a maritime osmoconformer. its native application of salts is less than that of the seawater it lives in. it is continually falling water from the gills to the ocean via osmosis.

countering that, the fish is going to be swallowing seawater. but since its internal collection of salts is lower than seawater, the fish will want to go free of excess salt, and since that's going upon a gradient, then active transport, requiring energy, must be used to pump out the salt. much marine fish use the organs to filter out the salt and these fish discharge very straight urine.