生物课本七年级下册电子版

生物课本七年级下册电子版
1.Living things are made up of cells.
2.Cells are the basic units of life.
3.Cells are too small to be seen with the naked eye.
4.Cells are the smallest units of life that can carry out all the activities of life.
5.Cells are made up of many parts, including a nucleus, cytoplasm, cell membrane, and organelles.
6.The nucleus is the control center of the cell.
7.The cytoplasm is the jelly-like material that fills the cell.
8.The cell membrane is a thin layer that surrounds the cell and controls what enters and leaves the cell.
anelles are tiny structures inside the cell that carry out specific functions.
10.Cells can reproduce by dividing into two new cells.
11.Cells can also exchange materials with their environment.
12.Cells can also respond to changes in their environment.
13.Cells can also grow and develop.
14.Cells can also die when they are no longer able to carry out their functions.
15.Cells come in many different shapes and sizes.
16.Cells can be single-celled or multi-celled.
17.Single-celled organisms are made up of one cell, while multi-celled organisms are made up of many cells.
18.Cells work together to form tissues, organs, and organ systems.
19.Tissues are made up of similar cells that work together to perform a specific function.
ans are made up of different types of tissues that work together to perform a specific function.
an systems are made up of different organs that work together to perform a specific function.
anisms are made up of many different organ systems that work together to keep the organism alive.。