Why don't all cells within a single kingdom look the same?

Cells within a single kingdom do not all look the same due to their specialized functions and adaptations to different environments. For example, in multicellular organisms, cells differentiate to perform specific roles such as muscle contraction, nutrient absorption, or immune response, leading to diverse shapes and structures. Additionally, evolutionary pressures and varying habitats can result in different cellular adaptations even within the same kingdom, contributing to the overall diversity of cell types.