Option C : oxygen and Option B: nutrients
Please, next time check your question carefully, because even if I am right there is possibility that it won't coincide with your options. And if my memory serves me well, the answer on the question is n<span>ot only does topsoil erosion lead to loss of soil fertility, it can also cause water pollution.</span>
Answer: It is important to control the variables so the evidence from the experiment are as accurate as possible.
Derived from the inner cells of a human blastocysts , a very early human embryo.
At the blastocyst stage, five to 10 days after fertilization,
the embryo is a cluster of 100-200 cells
