What is heterogeneous mixture and elements??? Help

A heterogeneous mixture is a type of mixture where the components are not uniform or consistent throughout and the individual substances can often be seen and separated physically. In a heterogeneous mixture, the different parts of the mixture are not uniformly mixed and might form separate layers or regions with distinct properties. Examples of heterogeneous mixtures include salad, a bowl of cereal with milk, and a rock with multiple minerals.

Elements, on the other hand, are substances that are made up of only one type of atom and cannot be broken down into simpler substances by chemical means. Elements are the basic building blocks of all matter and are defined by the number of protons found in their atomic nuclei. For example, carbon (C), oxygen (O), and gold (Au) are all elements. They can exist in different forms known as allotropes (like carbon in the form of diamond or graphite) but even in these different forms, they are still only made up of carbon atoms.