Which of the following best describes matter?

The definition of matter is comprehensive and encompasses a wide range of substances and forms. Matter is best described as anything that takes up space and has mass, making the definition chosen the most accurate. This includes solid, liquid, and gaseous states of materials, and it underlines the fundamental properties of matter.

Considering other choices, the first option suggests that matter is defined solely by its property of being dissolvable, which does not encompass all forms of matter, as many substances cannot dissolve at all. The third option refers to a specific scenario in which matter undergoes a chemical reaction, but it does not capture the broader definition applicable to matter as a whole. Lastly, the fourth option limits the definition to elements and their combinations, which excludes many other forms of matter that exist independently of elemental combinations, such as compounds or mixtures.

By focusing on both the requirement of occupying space and having mass, the correct choice reflects the broad and inclusive nature of matter.