Metabolism definition – Metabolism is the sum total of all chemical reactions (both anabolic and catabolic) occurring in a living system. So, is correct.

Universality – All living organisms, including plants, animals, fungi, and microbes, exhibit metabolism. So, is correct.

In vitro metabolic reactions – Some metabolic reactions can be studied outside the living organism (cell-free systems). These reactions are “living reactions” but not considered living entities themselves. So, is correct.