What is meant by matter?

Matter is defined as anything that occupies space and has weight. This definition applies universally to all physical substances, regardless of their state—solid, liquid, or gas. Matter encompasses a vast range of entities, from everyday objects like tables and chairs to invisible air and complex chemical compounds. One of the fundamental properties of matter is that it takes up space, meaning it has a volume, and its weight, which is a measure of the gravitational force acting on it, reflects the amount of matter present.

The other choices describe more specific conditions or types of matter, rather than providing a comprehensive definition. For instance, while a solid substance with a fixed shape is indeed matter, it does not account for liquids or gases, which do not maintain a fixed shape but still occupy space and have weight. Similarly, a fluid's ability to take the shape of its container is true, but it does not encompass solids or gases. The mention of a combination of elements in chemical form refers specifically to chemical substances, which are a subset of matter rather than an all-encompassing definition. Thus, the most accurate and broad definition of matter is indeed that it occupies space and has weight.