Answer:
At least 17 PCR cycles or 16 PCR cycles
Explanation:
As we know -
In one chain of heating and cooling of polymerase chain reaction (PCR), the strands of DNA gets doubled.
The general mathematical representation of this is

where "n" is the number of PCR cycles.
It is given that DNA strands to be produced is 16 times the original quantity of DNA.
So the PCR cycle must be carried out at least 17 times in order to have DNA strand not less than 16 times the original quantity of DNA
Answer:
Proteins is a macromolecule that helps to send signals
Organ system is the answer
Plant cells have what is perhaps the most complex outer coverings. Plant cell walls are made largely of cellulose which forms strong, highly rigid, almost indigestible coverings that protect the cell and gives it shape.