JavaScript, Mysterious Organism Project, Stuck on how to do step 4

Hi , I am stuck on step number 4. I understand what it is wanting me to do but I am struggling on how to implement it. I don’t want to cheat and just look at the solution. Could I get guidance how to set the mutate method to dna with .this keyword and how to change the mutate base and if it is the sane as the mockup Strand base.

This is what I have so far.

// Returns a random single stand of DNA containing 15 bases
const mockUpStrand = () => {
  const newStrand = []
  for (let i = 0; i < 15; i++) {
  return newStrand

const pAequorFactory = (specimenNum,dna) => {
  return {
    mutate() {
      const mutatestrand = []
      for(i = 0; i < 15; i++) {


console.log(pAequorFactory(1, mockUpStrand()))

Het there!
I’d like to help you if you still want it, can you share the link of the project so that I can give it a look? :slight_smile: