Article: Epigenetics is the study of mitotically and/or meiotically heritable changes in gene function that cannot be explained by changes in the underlying DNA sequence but cause the organism's genes to behave (or "express themselves") differently. One example of epigenetic change is the marking of the genes by DNA methylation which determines whether they will be expressed or not. Gene expression can also be controlled by repressor proteins that attach to silencer regions of the DNA and prevent that region of the DNA code from being expressed. Epigenetic marks may be added or removed from the DNA during programmed stages of development of the plant, and are responsible, for example, for the differences between anthers, petals and normal leaves, despite the fact that they all have the same underlying genetic code. Epigenetic changes may be temporary or may remain through successive cell divisions for the remainder of the cell's life. Some epigenetic changes have been shown to be heritable, while others are reset in the germ cells.

Question: Are the changes then presented, permanent?
Ans: may be temporary

Here is a question about this article: While inert gas reduces filament evaporation, it also conducts heat from the filament, thereby cooling the filament and reducing efficiency. At constant pressure and temperature, the thermal conductivity of a gas depends upon the molecular weight of the gas and the cross sectional area of the gas molecules. Higher molecular weight gasses have lower thermal conductivity, because both the molecular weight is higher and also the cross sectional area is higher. Xenon gas improves efficiency because of its high molecular weight, but is also more expensive, so its use is limited to smaller lamps.
What is the answer to this question: What affects the thermal conductivity of a gas?
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So... molecular weight of the gas and the cross sectional area of the gas molecules

The problem: Answer a question about this article:
Some experiments on very resinous Longleaf Pine specimens indicate an increase in strength, due to the resin which increases the strength when dry. Such resin-saturated heartwood is called "fat lighter". Structures built of fat lighter are almost impervious to rot and termites; however they are very flammable. Stumps of old longleaf pines are often dug, split into small pieces and sold as kindling for fires. Stumps thus dug may actually remain a century or more since being cut. Spruce impregnated with crude resin and dried is also greatly increased in strength thereby.
What type of tree has resin that makes it stronger when it dries?
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The answer: Longleaf Pine

Problem: Please answer a question about the following article about Detroit:
A number of the city's downtown employers are relatively new, as there has been a marked trend of companies moving from satellite suburbs around Metropolitan Detroit into the downtown core.[citation needed] Compuware completed its world headquarters in downtown in 2003. OnStar, Blue Cross Blue Shield, and HP Enterprise Services are located at the Renaissance Center. PricewaterhouseCoopers Plaza offices are adjacent to Ford Field, and Ernst & Young completed its office building at One Kennedy Square in 2006. Perhaps most prominently, in 2010, Quicken Loans, one of the largest mortgage lenders, relocated its world headquarters and 4,000 employees to downtown Detroit, consolidating its suburban offices. In July 2012, the U.S. Patent and Trademark Office opened its Elijah J. McCoy Satellite Office in the Rivertown/Warehouse District as its first location outside Washington, D.C.'s metropolitan area.
Which company moved it's world headquarters to Detroit in 2010?
A: Quicken Loans

Question: Read this and answer the question

Unlike animals, many plant cells, particularly those of the parenchyma, do not terminally differentiate, remaining totipotent with the ability to give rise to a new individual plant. Exceptions include highly lignified cells, the sclerenchyma and xylem which are dead at maturity, and the phloem sieve tubes which lack nuclei. While plants use many of the same epigenetic mechanisms as animals, such as chromatin remodeling, an alternative hypothesis is that plants set their gene expression patterns using positional information from the environment and surrounding cells to determine their developmental fate.

Why do phloem sieve tubes stop forming?
Answer: lack nuclei

The largest producers of cotton, currently (2009), are China and India, with annual production of about 34 million bales and 33.4 million bales, respectively; most of this production is consumed by their respective textile industries. The largest exporters of raw cotton are the United States, with sales of $4.9 billion, and Africa, with sales of $2.1 billion. The total international trade is estimated to be $12 billion. Africa's share of the cotton trade has doubled since 1980. Neither area has a significant domestic textile industry, textile manufacturing having moved to developing nations in Eastern and South Asia such as India and China. In Africa, cotton is grown by numerous small holders. Dunavant Enterprises, based in Memphis, Tennessee, is the leading cotton broker in Africa, with hundreds of purchasing agents. It operates cotton gins in Uganda, Mozambique, and Zambia. In Zambia, it often offers loans for seed and expenses to the 180,000 small farmers who grow cotton for it, as well as advice on farming methods. Cargill also purchases cotton in Africa for export.
In 2009 what were the largest producers of cotton?
China and India