In this topic you will learn about many kinds of plants and how they are used.

All plants share common traits, but some kinds of plants are harder to identify. A green chemical in plant cells that allows plants to use the Sun's energy to make food is called chlorophyll. Plants also need water and minerals from the soil and carbon dioxide from the air to make food.

When you look at a leaf under a microscope you can see little boxes. These are cells. All living things are made of cells. Plants are made up of many different kinds of cells. These cells work to keep the plants alive. Different kinds of cells do different kinds of jobs. Cells are organized into tissues. Some tissues carry water and minerals to various parts of the plant. Some tissues support the plant.

Scientists group living things by using the similar patterns found between them. This is called classification. By looking at what goes on inside plants, scientists have been able to separate plants into two large groups. One of these groups has lengths of tubelike cells that tunnel up and down the stem of a plant. Water taken in by the plant's roots moves up one set of tubes. Food made in the leaves moves down the other set of tubes. These tubes are called vascular tissue. Plants that contain tissue through which the water moves up and the food moves down are called vascular. Plants that do not have tissue through which water and food move are called nonvascular.

Plants can make their own food, but animals cannot. Animals also differ from plants because animals can move from one place to another. All animals are grouped into one kingdom. All plants are grouped into another kingdom. The next group division in both kingdoms is called the phylum.

Members of the fungus kingdom absorb food from their environment. They include yeasts, mildews, molds, mushrooms, and smuts. Some fungi have great flavors. Others contain chemicals that fight diseases. Still others put the bubbles in bread or turn cheese sharp and tangy.

Members of the protist kingdom contain one-celled and many-celled living things, some that make food and some that hunt for food. This kingdom includes slime molds, diatoms, euglenas, and green algae.

A bacterium is a member of one of two kingdoms of one-celled living things. A bacterium has no nucleus, or center, in its body. Some bacteria can cause infections. Others are necessary for plants and animals to survive. Some bacteria cause serious diseases like tuberculosis or pneumonia.

Life on Earth would be impossible without plants. Almost everything you eat comes from plants, or from animals that eat plants.