A ghostwriter is a professional writer who is paid to write books, articles, stories, reports, or other texts that are officially credited to another person. wikipedia.org

Physical fitness comprises two related concepts: general fitness (a state of health and well-being), and specific fitness (the ability to perform specific aspects of sports or occupations). It is generally achieved through correct nutrition, exercise, and enough rest. wikipedia.org

A literature review is a body of text that aims to review the critical points of current knowledge including substantive findings as well as theoretical and methodological contributions to a particular topic. wikipedia.org

A research paper is an academic work that is usually published in an academic journal. It contains original research results or reviews existing results. wikipedia.org

A tutor is an instructor who gives private lessons. wikipedia.org

Writing in these forms or styles is usually written in an impersonal and dispassionate tone, targeted for a critical and informed audience, based on closely investigated knowledge, and intended to reinforce or challenge concepts or arguments. wikipedia.org