Explain why the PCR has been dubbed a "chain reaction"

How many variables are altered in a good experiment? a.1 b.0 c.2 d.3

What is a limitation of using a chemical formula, such as c6h1206, to represent a compound? the chemical formula does not show the types of elements that make up the compound. the chemical formula does not show how the atoms are connected to one another the chemical formula does not show the number of atoms of each element in a molecule. the chemical formula does not show the chemical symbols of the elements in the compound

Does all the energy stored by the phytoplankton reach the top level of the pyramid