Page 1: Investigate the Evidence

Read each passage and study its visual. Then identify the component of cell theory that the source supports. Record one exact quoted phrase or one precise observation from the visual.

Word bank: living things • basic unit • pre-existing • evidence • supports • divide

Source A: Living Things Are Made of Cells

Every living organism is made of one or more cells. A bacterium is a single cell, while a dog, tree, or human is made of many different kinds of cells. In a multicellular organism, cells may have special jobs, such as carrying oxygen, absorbing water, or sending signals. Although organisms differ greatly in size and form, their bodies are built from cells. Scientists use microscopes to observe these cells in samples from plants, animals, and other living things.

Sentence starter: The source states, “________________________________________,” which supports __________________________________.

Source B: Cells Are the Basic Unit of Life

Cells are the smallest structures that can carry out all the processes needed for life. A labeled cell diagram may show a cell membrane, cytoplasm, and genetic material. These parts work together: the membrane controls what enters and leaves, the cytoplasm holds many chemical reactions, and genetic material provides instructions. Larger body structures, such as tissues and organs, are made from groups of cells. This organization helps explain why cells are called the basic unit of life.

Sentence starter: The diagram shows __________________________________, which supports __________________________________.

Source C: Cells Come From Pre-Existing Cells

New cells form when an existing cell divides. Before division, the cell copies its genetic material. The cell then separates into two daughter cells, each receiving genetic information. The daughter cells may grow and divide again. This process helps organisms grow, replace damaged cells, and reproduce. A cell-division diagram shows a sequence from one parent cell to two new cells. The sequence provides evidence that cells do not appear from nothing; they come from cells that already exist.

Sentence starter: The source shows or states __________________________________, which supports __________________________________.

Page 2: Build a Cell Theory Evidence Map

Place Cell Theory in the center of your map. Connect it to all three components. For each branch, include one evidence detail from Source A, B, or C and a linking phrase such as explains, supported by, or shows that.

Sentence starter: The components are connected because ________________________________.

Sentence starter: Cell theory explains that ____________________________________________. For example, Source _____ states or shows “________________________________________,” which supports this idea because ____________________________________________.