Why is muffin batter not considered a pure substance?

Muffin batter is not considered a pure substance because it is a mixture of various ingredients, such as flour, sugar, eggs, milk, and baking powder, each retaining its own chemical properties. Unlike a pure substance, which consists of only one type of particle, muffin batter contains multiple components that can vary in proportions and may undergo physical and chemical changes during baking. This combination leads to a heterogeneous mixture where the individual ingredients are not uniformly distributed.