In the context of production possibilities, how does the concept of diminishing returns affect opportunity cost and marginal cost when increasing production of one good over another?

Diminishing returns happen when we increase the production of one good while keeping resources for other goods the same. As we produce more of one good, like cars, it becomes harder and more expensive to make each additional car because we have to take resources away from making other goods, like bicycles. This means that the opportunity cost, which is what we give up to make more of the first good, increases. For example, if we shift resources to produce more cars, we might have to give up making more bicycles, and the amount of bicycles we lose for each extra car we produce will grow larger. Therefore, as we focus more on one product, both the opportunity cost and marginal cost of production rise due to the limited resources available.