Which of these is a possible risk associated with stem cell therapy?
a) the host’s body could reject the transplanted stem cells.
b) stem cells are totipotent and can form other cells or tissue types.
c) stem cells are multipotent and can form only a few other cell types.
d) stem cells could continue to differentiate after they are transplanted.

The correct answer is option  A)The host’s body could reject the transplanted stem cells.

Although the stem cells which are used to regenerate a particular organ are isolated from the bone marrow or adipose tissue of the patient itself, it still has the chances of rejection by the patient's body. This is known as graft rejection. Graft rejection occurs because the host's immune system considers the transplanted organ as foreign tissue and therefore, causes internal bleeding and tissue lysis. In such cases, immunosuppressants like glucocorticoids and corticosteroids are given to suppress the immune response. But, these drugs can cause many side effects to the host's body.

what have scientists found to be the most efficient and effective way to insert new sequences into an individual? a-scientists have created genetically altered foods that release dna during digestion. b-scientists use viruses to insert specific gene sequences. c-scientists irradiate genes so that they can be absorbed through the skin.

a fossil fuel is a fuel formed by natural processes, such as anaerobic decomposition of buried dead organisms, containing energy originating in ancient photosynthesis.[1] the age of the organisms and their resulting fossil fuels is typically millions of years, and sometimes exceeds 650 million years.[2] fossil fuels contain high percentages of carbon and include petroleum, coal, and natural gas.[3] other commonly used derivatives include kerosene and propane. fossil fuels range from volatile materials with low carbon to hydrogen ratios like methane, to liquids like petroleum, to nonvolatile materials composed of almost pure carbon, like anthracite coal. methane can be found in hydrocarbon fields either alone, associated with oil, or in the form of methane clathrates.

the theory that fossil fuels formed from the fossilized remains of dead plants by exposure to heat and pressure in the earth's crust over millions of years was first introduced by andreas libavius "in his 1597 alchemia [alchymia]" and later by mikhail lomonosov "as early as 1757 and certainly by 1763".[4] the first use of the term "fossil fuel" was by the german chemist caspar neumann, in english translation in 1759.[5]

in 2017 the world's primary energy sources consisted of petroleum (34%), coal (28%), natural gas (23%), amounting to an 85% share for fossil fuels in primary energy consumption in the world.[6] non-fossil sources in 2006 included nuclear (8.5%), hydroelectric (6.3%), and others (geothermal, solar, tidal, wind, wood, waste) amounting to 0.9%.[7] world energy consumption was growing at about 2.3% per year. in 2015 about 18% of worldwide consumption was from renewable sources.[8]