Explain prototypal inheritance and the prototype chain.

JavaScript uses prototypal inheritance: objects delegate property access to another object via an internal [[Prototype]] link (exposed as Object.getPrototypeOf(obj)).

When you read obj.prop, the engine:

1. Looks on obj itself.
2. If missing, follows [[Prototype]] and repeats.
3. Stops at null → returns undefined.

function Person(name) {
  this.name = name
}
Person.prototype.greet = function () {
  return `Hi, ${this.name}`
}

const alice = new Person('Alice')
Object.getPrototypeOf(alice) === Person.prototype // true
Object.getPrototypeOf(Person.prototype) === Object.prototype // true
Object.getPrototypeOf(Object.prototype) // null

vs classical inheritance: There are no classes at the language core (ES6 class is syntactic sugar over prototypes). Objects inherit directly from other objects through the chain.

Key APIs: Object.create(proto), Object.getPrototypeOf, Constructor.prototype.