What term describes the process where an organism transforms from immature to mature form?

The term that accurately describes the process where an organism transforms from its immature form to its mature form is metamorphosis. This term specifically refers to a distinct series of developmental stages that many organisms, particularly insects, undergo. For example, a caterpillar undergoes metamorphosis to become a butterfly, involving significant changes in form and function.

While development is a broader term that encompasses overall changes an organism experiences throughout its life, metamorphosis specifically highlights the transformative stage from one clearly defined form to another, making it the most accurate choice in this context. Similarly, growth refers to an increase in size or mass rather than a transformation in form. The life cycle encompasses the entire progression of an organism's life from birth to death but does not specifically highlight the transformation stage. Therefore, metamorphosis stands out as the most precise and relevant term for this process.