Final answer:
Matter is defined as anything that has mass and occupies space. Tangible objects such as a hot dog or a tree are examples of matter. Abstract concepts like ideas and dreams, however, do not meet the criteria of having mass and taking up space, so they are not considered matter.
Step-by-step explanation:
The question asks which items can be classified as matter. Matter is anything that has mass and takes up space. This includes all objects and substances we can interact with physically, such as solids, liquids, and gases. A few examples include a hot dog, a tree, and even the air we breathe. However, abstract concepts like ideas and dreams do not have mass nor do they occupy space, thus they are not considered matter. Ideas and dreams are the result of complex processes in our brains, but they are intangible and do not have a physical presence in the world.
When classifying matter, it's essential to distinguish between tangible objects and intangible concepts. This distinction helps in understanding the fundamental properties of what constitutes the physical world around us, as opposed to the non-material world of thoughts and emotions.