The answer is B :),this sentence has to be longer LOL
One reasonable plan would be to wear a face mask or surgical
mask. Take note that your surgical mask contains two sides – the white side and the
blue side. Since the main purpose of your mask usage is to prevent yourself
from inhaling too much bad air, the blue side of the mask should be the one
touching your skin. This is because the white side of your mask helps you
prevent from coming in contact with toxins that may come from the smog.
I would say energy myself, and this is because energy plays a key role in all of these. With trophic levels energy is being transferred amongst the levels. Food chain's is a map of how the energy is passed along the chain. Food web is a web of how energy is transferred, and this is why I would say energy is a keyword.
A codon<span> is a three-base sequence (three nitrogen bases in a row) on mRNA. It calls for a specific amino acid to be brought to the growing polypeptide. An </span>anticodon<span> is a three-base sequence on tRNA. It matches the </span>codon<span>.</span>