Question

What is used to sort dna into different lengths? apex?

Answer 1

I believe it is gel electrophoresis. 
Gel electrophoresis is a techniwue used to separate DNA fragments or other macromolecules such as RNA and proteins based on their size and charge. It can also determine the actual size of a piece of DNA by examining it next to a standard "yardstick" made up of DNA fragments of known sizes.

Answer 2

Answer: Gel Electrophoresis.

Explanation: Gel Electrophoresis is a laboratory technique by which DNA fragments of different sizes can be sorted according to the molecular sizes.

The fragments of the different sizes of DNA move by the effect of the electrical field through a gel that contains small pores.

This gel contains a DNA ladder that has different base pairs indicated on it which is used to determine the size of the DNA fragments.