1. The sizes of their necks vary
Gel electrophoresis is a method of genetic analysis which involves seperating segments of DNA based on their size and charge.
It involves cutting DNA with various enzymes, then placing the DNA in an agarose gel. An electrical current is then run through the gel. Because DNA is a polar molecule the DNA segments will travel through the agarose cell as the current is applied. Larger fragments will travel shorter distances than shorter fragments. Two plates with 2 different DNA samples will be conducted and the orientation of the DNA strands will be used to make an analysis by comparing the 2 plates.
Obtaining mRNA from the cell, then using reverse transcriptase enzyme to convert it into a stable cDNA (or copy of DNA) molecule for insertion into the bacterial cell.
I hope this helps!
Porosity
Porosity refers to the space inside the rock that is taken up by pore space.