All land plants are multicellular. Nearly all plants are autotrophs. All plants must undergo photosynthesis in order to make food and survive. Plants have specialized structures that perform different functions. For example, a strong, rigid cell wall will support and protect the plant's cell.

A group of similar cells that perform a specific function are called tissues. Some plants have vascular tissue. The cells that make up vascular tissue work together to transport water, food, and minerals through a tube-llike structure. Plants without a vascular tissue will be a low-growing plant that lacks mineral transportation.

All organisms are classified according to how they are related to other organisms by comparing DNA, body structure, and development. All animals are classified based on whether they have a backbone or not. Animals like tigers, foxes, and monkeys have backbones. Animals like snails and slugs jellyfish.

Most animals are invertebrates. Invertebrates are animals without a backbone, and vertebrates are animals with backbones. Invertebrates are divided into six groups. Vetebrates need a backbone because it protects the nerve cord.