We group artworks with similar characteristics into periods or styles because it is easiest to do it that way - this way we can find common characteristics in these literary/artistic eras, and name them. For example, the Renaissance had a distinct style, which differs greatly from that of Romanticism.
Change the pH and the enzyme<span> stops working. Increasing the temperature to 60°C will cause a permanent change to the shape of the active site. This is why </span>enzymes<span> stop working when they are heated. We say they have become </span>denatured<span>.</span>
Gallons. You buy gasoline by the gallon.
Introduced species can harm our planet because in some regions of the world we are not prepared for their type of species, which can all in all cause damage.
I think it is A to, since the tissues are the closet thing to cell, which microscopic anatomy studies.