Eukaryotes form the third major domain of living organisms. In contrast to prokaryotes, they all have a cell nucleus, many cell organelles and linear chromosomes. Most eukaryotes have no cell wall, with the exception of plants. Eukaryotes include humans and most other animals, plants, fungi and algae.
Explanation for children:
An important component of eukaryotic cells is the cell nucleus. You can imagine it as a small peach stone and the fruit pulp is the rest of the cell. It has many important functions and also contains our DNA. All our characteristics are stored there, such as eye color, hair color, etc. Eukaryotes include humans and most plants and animals.