Stem cell therapies are not new. Doctors have been performing bone marrow stem cell transplants for decades. But when scientists learned how to remove stem cells from human embryos in 1998, both excitement and controversy ensued.
The excitement was due to the huge potential these cells have in curing human disease. The controversy centered on the moral implications of destroying human embryos. Political leaders began to debate over how to regulate and fund research involving human embryonic stem (hES) cells.
Newer breakthroughs may bring this debate to an end. In 2006 scientists learned how to stimulate a patient's own cells to behave like embryonic stem cells. These cells are reducing the need for human embryos in research and opening up exciting new possibilities for stem cell therapies.
Answer and Explanation:
The use of pesticides and fertilisers leads to soil pollution. These are often not easily biodegradable and so they accumulate in the soil and kill soil organisms. Rain water run-off may carry such chemicals into streams,rivers and lakes. These toxic chemicals can eventually find their way into the tissues of different organisms associated with aquatic ecosystem.
The accumulation of silt due to poor cultivation along the river banks and the destruction of riverine leads to soil erosion. The deposition of silt near the mouth of river makes the water turbid and so impedes the penetration of sunlight. This affects the aquatic organisms and pollute the water.
The closest answer would be A. Fertilization takes place in the Fallopian tube which is close to the ovary.
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1) F = m.a
Here, F= 99N, a = 12.5 m/s^2
m = F/a
m = 99/12.5
m = 7.92 Kg
The ultimate source of energy to support most life on earth is Sunlight .
