solution-part-2.js

var Person = function (first, last) {
  this.firstName = first;
  this.lastName = last;
};

Object.defineProperty(Person, 'species', {
  writable: false,
  value: 'human'
});

Object.defineProperty(Person, 'fullName', {
  get: function () {
    return this.firstName + ' ' + this.lastName;
  },
  set: function (value) {
    var splitString = value.trim().split(' ');

    if(splitString.length === 2) {
      this.firstName = splitString[0];
      this.lastName = splitString[1];
    }
  }
});

var woman = new Person('Kate', 'Khowalski');

woman.firstName; // 'Kate'
woman.lastName; // 'Khowalski'
woman.fullName; //'Kate Khowalski
woman.species; // human

/*
 * Change name
 */

woman.firstName = 'Yulia';
woman.firstName; // 'Yulia'
woman.lastName; // 'Khowalski'
woman.fullName; // 'Yulia Khowalski'
woman.species = 'fish';
woman.species; // human - No, you can't change this properity.

 /*
  * Change fullName
  */

woman.fullName = 'Joana Stevens';
woman.firstName; //Joana
woman.lastName; //Stevens